TWI886570B - Pelletized metal-decorated materials - Google Patents

Abstract

Inventive techniques for forming unique compositions of matter are disclosed, as well as various advantageous physical characteristics, and associated properties of the resultant materials. In particular, metal(s) (including various alloys, such as Inconel superalloys) are characterized by having carbon disposed within the metal lattice structure thereof. The carbon is primarily, or entirely, present at interstitial sites of the metal lattice, and may be present in amounts ranging from about 15 wt% to about 90 wt%. The carbon, moreover, forms non-polar covalent bonds with both metal atoms of the lattice and other carbon atoms present in the lattice. This facilitates substantially homogeneous dispersal of the carbon throughout the resultant material, conveying unique and advantageous properties such as strength-to-weight ratio, density, mechanical toughness, sheer strength, flex strength, hardness, anti-corrosiveness, electrical and/or thermal conductivity, etc. as described herein. In some approaches, the composition of matter may be powderized, or the powder may be pelletized.

Description

Pelletized Metal Decorative Materials

The present disclosure generally relates to the production and use of carbon-containing alloys in induction melting furnaces.

Specialty alloys are melted in vacuum induction melting (VIM) furnaces. The crucible of such VIM furnaces is used to melt and mix the various mixture components (e.g., metals and non-metals). Once the various combinations of metals are mixed, the melt can be dropped (e.g., poured) into a mold and cooled. Some mixtures include powdered ingredients. Unfortunately, the electromotive force from the induction coil of the VIM furnace acts on the powder to cause the powder to eject from the VIM furnace. This prevents the powder from mixing with other ingredients. Improved methods for using powdered ingredients in vacuum induction melting furnaces are needed.

As used herein, the term "covetic material" refers to a metal containing nano-sized carbon particles. Covetic materials are desirable in a variety of applications because they possess many physical, chemical, and electrical properties that exceed the capabilities of traditional non-carbon-containing materials.

The content of the present invention is provided to introduce a series of concepts further described in the specific implementation below in a simplified form. The content of the present invention is not intended to identify the key features or essential features of the subject matter claimed for protection, nor is it intended to limit the scope of the subject matter claimed for protection. In addition, the systems, methods, and devices of the present disclosure each have several innovative aspects, and a single aspect of these innovative aspects is not only responsible for the desired properties disclosed herein.

Various embodiments of the subject matter disclosed herein generally relate to apparatus, methods, and various compositions of carbon-metal composite materials. The apparatus shown and discussed may be associated with the controlled use of a plasma spray torch apparatus to produce various carbon-metal bonded compositions of matter, which are generally referred to as "covetic materials" in this disclosure. In some cases, the materials are metal-decorated carbon. In some cases, the materials are carbon-decorated metal. In other aspects, as described in more detail below, carbon may be combined with materials other than metals (such as ceramics, plastics, composites, silicon, etc.).

One configuration of a plasma spraying torch is embodied as an apparatus having a reaction chamber configured to receive a hydrocarbon process gas mixed with a plurality of molten metal nanoscale-sized particles, a microwave energy source operatively coupled to the reaction chamber to provide power to the reaction chamber, and a controller for adjusting the microwave energy source to create conditions in the reaction chamber such that the hydrocarbon process gas dissociates into its constituent carbon atoms and single-layer graphene (SLG) or few-layer graphene (FLG) grows from the carbon atoms onto the molten metal nanoscale-sized particles to form a plurality of carbon-metal nanoscale-sized particles. In some configurations, conditions in the reaction chamber cause: (i) a first temperature at which carbon atoms dissolve into molten metal nano-sized particles; and (ii) a second temperature at which at least some of the dissolved carbon atoms combine with the molten metal in a crystalline configuration. Some configurations of the apparatus utilize a cooling zone to cool the plurality of carbon-metal nano-sized particles into a powder form that can be collected and stored in a storage container proximate to and juxtaposed with the reaction chamber.

According to various embodiments, the inventive concept disclosed herein may be embodied as a composition of matter having any of the following physical and/or structural characteristics and associated properties. In addition, according to different embodiments, these characteristics and/or properties may be included in different combinations or arrangements, but are not limited.

In one aspect, a composition of matter comprises one or more particles, and each particle independently comprises a metal lattice having one or more coherent planar graphene layers disposed therein. Preferably, at least some of the carbon atoms of the one or more coherent planar graphene layers are disposed in interstitial sites within the metal lattice. More preferably, the one or more coherent planar graphene layers are interstitially interlaced between basal planes of the lattice. Graphene can exist as a single layer (e.g., "single-layer graphene" or "SLG") or multiple layers (e.g., two layers, three layers, five layers, ten layers, or any number of layers up to fifteen, also referred to herein as "few-layer graphene" or "FLG"). At least some of the carbon atoms of the one or more graphene layers are covalently bonded to metal atoms of the metal lattice, and the covalent bonds between the carbon atoms and the metal atoms are non-polar covalent bonds or include non-polar covalent bonds. In some embodiments, the covalent bonds may consist essentially of or entirely of non-polar covalent bonds. Similarly, the carbon atoms of the one or more graphene layers may be covalently bonded to other carbon atoms of the one or more graphene layers, and according to different embodiments, these covalent bonds may include non-polar covalent bonds, consist essentially of non-polar covalent bonds, or consist entirely of non-polar covalent bonds. Therefore, the one or more particles may include substantially or entirely no polar covalent bonds. Likewise, the metal lattice of each particle may include substantially or completely no ionic bonds. The one or more graphene layers are each preferably substantially free of defects, such that the graphene is "pristine". Preferably, each particle is also characterized by a substantial lack or more preferably a complete lack of carbon aggregates and/or agglomerates at the grain boundaries and/or at the surface of the metal lattice. Due to the innovative processing techniques described herein, the total carbon loading of the particles can range from about 15 wt % to about 90 wt %, with various intermediate loadings also being shown (e.g., in various embodiments, about 20 wt %, about 25 wt %, about 33 wt %, about 40 wt %, about 50 wt %, about 60 wt %, about 75 wt % or up to 90 wt %). Additionally, the particles may be characterized by a diameter in the range of about 20 nm to about 3.5 μm, and/or have a maximum discernible feature size in the range of about 0.1 nm to about 1 μm. In some embodiments, the particles may be pressed into pellets.

According to another aspect, a composition of matter includes an inconel nickel alloy having carbon disposed in its crystal lattice. Preferably, at least some of the carbon is disposed at interstitial sites of the metal lattice, and more preferably, the carbon is substantially uniformly dispersed in the metal lattice. Furthermore, in some embodiments, the grain boundaries of the composition of matter and/or the surfaces of the metal lattice are substantially free of carbon aggregates and/or agglomerates. Thus, the maximum discernible feature size of the composition of matter can be in the range of about 0.1 nm to about 1 μm. At least some of the carbon atoms are covalently bonded to metal atoms of the metal lattice, and the covalent bonds between the carbon atoms and the metal atoms are or include non-polar covalent bonds. In some embodiments, the covalent bonds may consist essentially of or consist entirely of non-polar covalent bonds. Similarly, carbon atoms may covalently bond to other carbon atoms, and depending on the embodiment, such covalent bonds may include, consist essentially of, or consist entirely of non-polar covalent bonds. Thus, the one or more compositions of matter may consist essentially of or consist entirely of polar covalent bonds. Similarly, a metal lattice may consist essentially of or consist entirely of ionic bonds.

According to another aspect, a composition of matter includes a metal lattice having at least about 15 wt% carbon disposed therein. Preferably, at least some of the carbon is disposed at interstitial sites of the metal lattice, and more preferably, the carbon is substantially uniformly dispersed in the metal lattice. Furthermore, in some embodiments, the grain boundaries of the composition of matter and/or the surfaces of the metal lattice are substantially free of carbon aggregates and/or agglomerates. Thus, the maximum discernible feature size of the composition of matter may be in the range of about 0.1 nm to about 1 μm. At least some of the carbon atoms are covalently bonded to metal atoms of the metal lattice, and the covalent bonds between the carbon atoms and the metal atoms are or include non-polar covalent bonds. In some embodiments, the covalent bonds may consist essentially of or consist entirely of non-polar covalent bonds. Similarly, depending on the embodiment, carbon atoms may be covalently bonded to other carbon atoms, and such covalent bonds may include, consist essentially of, or consist entirely of non-polar covalent bonds. Thus, the one or more compositions of matter may include essentially or entirely no polar covalent bonds. Similarly, a metal lattice may include essentially or entirely no ionic bonds.

In various embodiments of the foregoing aspects, the metal lattice may include one or more metals selected from the group consisting of aluminum, copper, iron, nickel, titanium, tungsten, chromium, molybdenum, cobalt, manganese, niobium, and combinations thereof. Thus, the metal lattice may be characterized by a crystal structure such as face-centered cubic (FCC), body-centered cubic (BCC), or hexagonal close-packed (HCC). In addition, the metal lattice may include about 15 wt % to about 90 wt % carbon (e.g., about 20 wt %, about 25 wt %, about 33 wt %, about 40 wt %, about 50 wt %, about 60 wt %, about 75 wt %, or up to 90 wt % in various embodiments). The carbon is preferably present at interstitial sites of the metal lattice. In some methods, the metal may be present in alloy form. For example, in particularly preferred methods, the metal may be in the form of one or more Inconel nickel alloys, such as Inconel 600, Inconel 617, Inconel 625, Inconel 690, Inconel 718 and/or Inconel X-750. More preferably, the Inconel nickel alloy is a superalloy.

The following drawings and specification describe in detail one or more embodiments of the subject matter described in this disclosure. Other features, aspects, and advantages will become apparent from the specification, drawings, and claims. It should be noted that the relative dimensions of the following drawings may not be drawn to scale.

105: Image

106: Homogeneous image

114: High-resolution transmission electron microscopy images

116: High-resolution energy dispersive spectroscopy x-ray imaging

500:Dual plasma torch equipment

600: Pulsed microwave plasma spraying torch equipment

604: Additional port

605: Hydrocarbon process gas

900: Scanning electron microscope image

1100: Plasma flame equipment

1202: Process gas port

1203 ₁ : Additional port

1203 ₂ : Additional port

1204:Entrance

1300: Pulsed microwave plasma spraying waveguide equipment

1600: Plasma spraying equipment

1700:Surface wave plasma system

1803: Growth plate

1810: Axial field configuration

1812: Gas input

1814: Plasma Flame

1816:Substrate

1818: Metal and/or carbon particles

1820: Radial field configuration

1821: Acceleration zone

1822: Microwave energy

1823: Collision zone

1824: Quenching layer

1862: Input port

2052: Carbon

2054: Copper

2062: Top surface area

2064: covetic material area

2066: Main metal area

2072: Area with higher carbon content

2074: Area with higher metal content

2104: First Area

2106: Second Area

2108: Molten metal

2110: Microwave reactor outlet

2112:Spraying materials

2114: Obtained deposition material

2116:Target substrate

2209: Melting equipment

2310:Flexible substrate

26E00: covetic material

27A00: Exemplary apparatus for producing powdered covetic material

27B00: Fluidized bed equipment

2702: Cooling area

2704: Collection container

2710: Powdered covetic material

2750: Fluidized bed

2752: Power supply

2756 ₁ : First Powder

2756 ₂ : Second Powder

2760:Heat source

2762: Cone-shaped body

3002: Vacuum environment

3004: Powdered material

3006: High power current generator

3008: Pellets

3102: Gas-solid separator container

3104: Powdered materials

3106: Granulator

3106a:Mold

3108: Pellets

3108a: Natural graphene

3108b:Metallic decorative carbon

3110:VIM processor

3112: The resulting melt

3202: Mould

The implementation of the subject matter disclosed herein is shown by way of example and is not intended to be limited by the figures in the accompanying drawings. Throughout the drawings and the specification, like element symbols represent like elements. It should be noted that the relative dimensions of the following figures may not be drawn to scale.

FIG. 1A is a comparative diagram showing two different covetic material forming techniques and exemplary materials produced by applying each of the covetic material forming techniques, according to some embodiments.

FIG. 1B presents a high-resolution transmission electron microscopy image and a high-resolution energy dispersive spectroscopy x-ray image of a material (e.g., a covetic material) produced according to the innovative techniques described herein, according to some embodiments.

FIG. 2 depicts a fabrication process for growing graphene onto small molten particles according to one or more of the disclosed embodiments.

FIG. 3 depicts a plasma energy profile diagram showing how a pulsed microwave energy source may be used to grow graphene onto small molten particles in accordance with one or more of the disclosed embodiments.

FIG. 4 depicts an electronic temperature control technique for growing graphene onto small molten particles according to one or more of the disclosed embodiments.

FIG5 illustrates a dual plasma torch apparatus for growing graphene onto small molten particles according to one or more of the disclosed embodiments.

FIG6 shows a pulsed microwave plasma spray torch apparatus adapted for growing graphene onto small molten particles according to one or more of the disclosed embodiments.

FIG. 7 is a diagram depicting the intersection of common subject areas associated with covetic (or related materials), plasma torch coating, and/or robust synthetic composite carbon coatings according to one or more of the disclosed embodiments.

8A-B are schematic diagrams depicting a plasma spraying process for spraying carbon particles onto small molten particles according to one or more of the disclosed embodiments.

FIG. 9 is a scanning electron microscope image showing the effect of spraying carbon particles onto small molten particles according to one or more of the disclosed embodiments.

FIG. 10 shows a graph depicting a graphene growth temperature curve and a binary phase diagram according to one or more of the disclosed embodiments.

Figure 11 is a cross-sectional view of a conventional plasma flame device.

FIG. 12 depicts a pulsed microwave process flow for use in growing graphene onto small molten particles according to one or more of the disclosed embodiments.

Figure 13 is a perspective view of a conventional pulsed microwave plasma spraying waveguide apparatus for growing graphene onto small molten particles.

FIG. 14 is a schematic depiction of a micro-welding technique for growing graphene onto small molten particles according to one or more of the disclosed embodiments.

FIG. 15 is a schematic depiction of a plasma spraying apparatus in a coaxial configuration according to one or more of the disclosed embodiments.

FIG. 16 is a schematic depiction of a plasma spraying apparatus showing the evolution of a material being processed by undergoing a series of non-equilibrium energy conditions according to one or more of the disclosed embodiments.

FIG. 17 depicts a surface wave plasma system for growing graphene onto molten particles according to one or more of the disclosed embodiments.

Figures 18A1-2, 18B, 18C, and 18D depict various configurations of a plasma spray reactor according to one or more of the disclosed embodiments.

FIG. 19 is a graph depicting energy versus time during pulse on and pulse off according to one or more of the disclosed embodiments.

FIG. 20A1 is an image depicting organometallic bonding that occurs when combining carbon and copper using a plasma spray torch according to some of the disclosed embodiments.

FIG. 20A2 is an image of a graded material composition applied to a substrate material and showing multiple (e.g., three) material property regions according to some of the disclosed embodiments.

FIG. 20B is a material evolution diagram depicting several layered configurations that occur when carbon is added to bulk aluminum according to one or more of the disclosed embodiments.

FIG. 21A depicts an apparatus for spraying a molten mixture of materials into a substrate according to one embodiment.

FIG. 21B depicts a method for spraying a material (e.g., a covetic material) into a substrate according to one or more of the disclosed embodiments.

FIG. 21C is a schematic diagram illustrating a plasma spraying process for spraying a film according to one or more of the disclosed embodiments.

FIG. 22A depicts an apparatus for encapsulating carbon particles with a molten material (e.g., metal) according to one or more of the disclosed embodiments.

FIG. 22B depicts a method for encapsulating carbon particles with a molten material (e.g., metal) according to one or more of the disclosed embodiments.

Figures 23A, 23B, 23C, and 23D depict exemplary deposition techniques according to one or more of the disclosed embodiments.

FIGS. 24A and 24B depict simplified schematic diagrams of materials according to one or more of the disclosed embodiments, which are formed by known deposition techniques for placing the materials on a substrate.

Figures 25A and 25B depict simplified schematic diagrams of materials formed using innovative deposition techniques that produce non-polar covalent bonding at the surface of a substrate in accordance with one or more of the disclosed embodiments.

Figures 26A, 26B, 26C, 26D, and 26E depict schematic diagrams showing how nonpolar covalent bonds are formed between sites in the square shape of the face-centered cubic (FCC) structure of aluminum and sites in the hexagonal shape that occur in certain crystal structures of carbon.

FIG. 27A depicts an exemplary apparatus for producing a material in powder form (e.g., a covetic material) according to one or more of the disclosed embodiments.

Figures 27B1 and 27B2 depict exemplary fluidized bed apparatus for cooling and processing powdered materials (e.g., powdered covetic) in a fluid according to one or more of the disclosed embodiments.

FIG. 27C is a schematic diagram illustrating a plasma spraying process for producing a powdered material (e.g., a powdered covetic material) according to one or more of the disclosed embodiments.

FIG. 28 depicts a method for manufacturing a component from a powdered material (e.g., a powdered covetic material) using injection molding techniques according to some embodiments.

FIG. 29 depicts various properties of materials described herein, including covetic materials, according to various embodiments.

Figures 30A1 and 30A2 illustrate problems and solutions associated with melting a powder (e.g., metal-decorated carbon) compared to melting the same or similar material in pellet form, according to some embodiments.

FIG. 31 depicts a method for using pellets to minimize or eliminate material ejection during introduction of the pellets into a VIM furnace according to some embodiments.

FIG. 32 depicts a melt placed into a mold according to some embodiments.

FIG. 33 depicts a simplified schematic diagram of a puck processing technique and apparatus according to one embodiment.

FIG. 34 shows a simplified schematic diagram of a spherical cake dispersion test process according to one method.

Related applications

This patent application is an international application claiming priority to U.S. Patent Application No. 17/957,937, filed on September 30, 2022, entitled “USING PELLETIZED METAL-DECORATED MATERIALS IN AN INDUCTION MELTING FURNACE” (subsequently published as U.S. Patent Publication No. 2023-0145800 under the same title on May 11, 2023); and U.S. Patent Application No. 17/957,937, filed on September 30, 2022, entitled “USING PELLETIZED METAL-DECORATED MATERIALS IN AN INDUCTION MELTING FURNACE" (subsequently published as U.S. Patent Publication No. 2023-0040722 under the same title on February 9, 2023). The disclosures of all prior applications are deemed to be part of and incorporated by reference into this patent application. The disclosures of all prior applications are deemed to be part of and incorporated by reference into this patent application.

Aspects of the present disclosure relate to methods for producing covetic materials using spraying techniques rather than by mixing carbon-based materials into a bulk molten metal slurry. Some embodiments relate to techniques for reducing the size of interstitial carbon structures to the nanometer (nm) scale. The figures and discussion herein present exemplary environments, exemplary systems, and exemplary methods for producing "covetic" materials, which are generally understood and defined herein as implying high concentrations (>6% wt and up to 90% wt) of carbon that are integrated into other materials (such as metals, metal-containing materials, plastics, composites, ceramics, etc., as described herein, according to various embodiments) in a manner that the carbon does not separate during melting or magnetron sputtering. The resulting material has many unique and improved properties compared to the base material from which it is produced. The carbon is dispersed in a (e.g., metal) matrix in several ways that help improve the material's properties. For example, the carbon is very strongly bonded to the resulting material (e.g., covetic material), often resisting many standard methods in detecting and characterizing its form. The inclusion of nanoscale carbon increases the melting point and surface tension of the resulting material. Materials produced according to the techniques described herein have increased hot and cold working strength.

Identification and importance of problems and opportunities

Metal matrix composites may consist of (at least) a metal or metal alloy (meaning a metal made by combining two or more metallic elements, particularly to impart greater strength or corrosion resistance) matrix in combination with a high strength modulus ceramic, carbon-based reinforcements or microfillers in the form of continuous or discontinuous fibers, whiskers or particles. The size of the reinforcement is important, as micron-sized reinforcements may exhibit strength and stiffness higher than the base alloy to acceptable levels. However, such improvements may also be accompanied by undesirably poor ductility and undesirably low yield strength, machinability and fracture toughness under critical loads due to undesirable, non-uniform placement of carbon between grains (e.g., at grain boundaries) during processing. Reducing the size of the reinforcement phase to the nanoscale is critical to avoid premature cracking and other drawbacks of metal matrix composites with incompatible micron-sized reinforcements. Furthermore, methods are needed to allow the reinforcement phase to be incorporated into a matrix (e.g., a metal alloy) and, optimally, to be incorporated uniformly into the matrix.

Commensurate with the addition of the above-mentioned carbon-based reinforcements, significant improvements in mechanical, thermal, electrical, and tribological (the science and engineering of surfaces interacting in relative motion) properties have been observed. Notably, such properties may change and/or improve when the size of the reinforcement is reduced from the micron scale (e.g., 1-1000 μm) to the nanoscale (e.g., <100 nm) due to increased cohesion between the matrix and the particles. The improvement in properties can be attributed to the formation of strong interfaces that promote efficient reinforcement mechanisms. It has been reported that tensile strength and yield strength are enhanced for nanosized particles (~20 nm) compared to micron-sized particles (~3.5 μm), although the volume loading of the nanosized particles is reduced by an order of magnitude compared to the micron-sized particles. Therefore, prior art techniques known in the art, such as induction melting, plasma spark sintering, etc., are generally unable to provide nanoscale reinforcements. Therefore, there is a need to reduce carbon structures containing interstitial vacancies therein to the nanoscale.

Microwave (MW) Plasma Torch Reactor

Using a microwave (MW) plasma torch reactor, pristine 3D few-layer graphene (FLG) particles can be continuously nucleated, such as in flight in an atmospheric pressure vapor stream of a carbonaceous material such as methane gas, wherein such nucleation occurs in initially synthesized carbon-based or carbon-containing "seed" particles. Evident highly structured and tunable 3D mesoporous carbon-based particles composed of multiple layers of FLG (e.g., 5-15 layers) grow from the carbonaceous material, accompanied by the incorporation of metal elements or metal-based alloys to form at least partially covalently bonded (and at least partially metallically or ionically bonded) carbon-metal composite (also referred to herein as "covetic") particle structures. In some embodiments, the "pristine" graphene (referring to graphene with no defects or few defects) provided or produced in the described MW torch reactor is not oxidized or contains an extremely low (e.g., <1%) oxygen content. In some embodiments, the metal (in the resulting covetic material) itself is held together by metallic bonding, and the carbon (as commonly found in graphene or some other organized carbon-based 2D or 3D structure such as a matrix or lattice) itself is held together (primarily) by non-polar covalent bonds. The composite carbon-metal structure may include non-polar covalent bonds between carbon atoms and metal atoms occurring at the metal-carbon interface. In a preferred embodiment, the covalent bonds between carbon atoms and/or between carbon atoms and metal atoms present in the composition of matter consist essentially of or entirely of non-polar covalent bonds.

In addition, carbon can be present in amounts that cannot be achieved using conventional techniques, for example, according to various embodiments, the resulting material can contain greater than about 6wt% carbon, greater than about 15wt% carbon, greater than about 40wt% carbon, greater than about 60wt% carbon, or up to about 90wt% carbon. In various embodiments, carbon can be included in the metal lattice in the aforementioned amounts such that all or substantially all of the carbon is incorporated into the metal (or other material) lattice and the grain boundaries/lattice surfaces are substantially or completely free of carbon aggregates and/or agglomerates. In addition, the carbon is preferably located at interstitial sites of the lattice.

In particularly preferred embodiments, the material may be provided in the form of a powder having the physical properties of a "covetic" material as described herein. The powder may comprise a plurality of particles, e.g., particles having a diameter of about 20 nm to about 3.5 μm, wherein each particle comprises metal-decorated carbon (in the form of carbon on metal or metal on carbon) having carbon disposed in a metal lattice as described herein. Optimally, the particles each independently comprise a metal lattice having one or more (e.g., one, two, five, ten, or up to fifteen) coherent planar graphene layers disposed in the metal lattice. FIG. 21C and FIG. 27C illustrate exemplary cross-sectional structures of such coherent planar graphene layers disposed along a basal plane of an aluminum substrate according to one aspect of the presently described inventive concepts. Those skilled in the art will appreciate that various embodiments of the presently described powders may include particles exhibiting such cross-sectional structures. In fact, as the carbon is incorporated into the crystal lattice, the carbon advantageously penetrates into the basal plane surfaces rather than being deposited at grain boundaries (or other lattice surfaces). This process is possible due to the wettable nature of nanoscale graphene and is not observed when producing carbon implanted materials using known techniques.

In various aspects, at least some of the carbon atoms of the one or more coherent planar graphene layers are disposed in interstitial sites within the metal lattice, and preferably, the one or more coherent planar graphene layers are juxtaposed parallel to the basal planes of the metal lattice. In some embodiments, the one or more coherent planar graphene layers are interstitially juxtaposed between the basal planes of the metal lattice. In some embodiments, the one or more coherent planar graphene layers are interstitially staggered between the basal planes of the metal lattice. Those skilled in the art will appreciate after reading this disclosure that this unique dispersion of carbon at interstitial sites and arrangement relative to the basal planes of the crystal lattice occurs because of the innovative processing described herein, which exploits the high "wettability" of nanoscale graphene (particularly pristine graphene) and, as described herein, achieves high carbon loadings, substantially uniform dispersion of carbon, and a substantial lack of carbon aggregates and/or agglomerates, all of which are not achievable using conventional techniques. See, e.g., FIGS. 1A-1B for a graphical comparison of conventionally produced "covetic materials" compared to materials produced using the innovative techniques described herein, and the corresponding description below.

With continued reference to the powdered material according to the present disclosure, at least some of the carbon atoms may be covalently bonded to metal atoms of the metal lattice while also allowing for non-polar covalent bonding between carbon atoms and/or metallic bonding between metal atoms of the material. More specifically, non-polar covalent bonding between carbon atoms and/or between carbon atoms and metal atoms is characterized by equal sharing of electrons between the bonded atoms, as opposed to polar covalent bonding (where electrons are shared between bonded atoms) or ionic bonding (where bonded atoms are held together by charge differences following the transfer of electrons from one atom to another). In some aspects, particles of the powdered material may include substantially or entirely no polar covalent and/or ionic bonds. In this context, "substantially" free of polar covalent and/or ionic bonds refers to a composition whose properties (e.g., crystal structure, mechanical strength, thermal/electrical conductivity, reflectivity, etc., as described below, and in particular, see FIG. 29 ) are not due to the presence of polar covalent and/or ionic bonds. A composition that is substantially free of polar covalent and/or ionic bonds can be considered to consist essentially or entirely of non-polar covalent bonds, at least with respect to the carbon atoms and metal atoms bonded together within the structure.

Furthermore, graphene is preferably "pristine" in that the 2D or 3D structure is substantially free of defects, such as vacancies, inclusions, contaminants, etc., as will be understood by one of ordinary skill in the art after reading this disclosure.

The metal lattice may include one or more metals, such as aluminum, copper, iron, nickel, titanium, tantalum, tungsten, chromium, molybdenum, cobalt, manganese, niobium, and combinations thereof. Where a combination is included, the metal is preferably in the form of an alloy, such as an Inconel nickel alloy, preferably Inconel nickel formed of nickel, chromium, aluminum, copper, iron, titanium, tantalum, molybdenum, cobalt, manganese and/or niobium, and most preferably, the Inconel nickel superalloy is Inconel 600, Inconel 617, Inconel 625, Inconel 690, Inconel 718, Inconel X-750, or combinations thereof. In some cases, the combination includes tin and/or tungsten, and/or silver, and/or antimony, either alone or in combination. In some embodiments, one or more of the foregoing metals may be used alone or in combination as a surfactant to improve the wettability of the metal-carbon combination.

The powdered material as described herein is preferably formed using a non-equilibrium plasma, such as may be produced using a microwave plasma-based reactor as described herein. The microwave plasma-based reactor process disclosed herein provides a reaction and processing environment in which gas-solid reactions can be controlled under non-equilibrium conditions (referring to a physical system that is not in thermodynamic equilibrium but can be described by variables that represent extrapolations of variables used to specify a system in thermodynamic equilibrium; non-equilibrium thermodynamics involves transport processes and chemical reaction rates, and the initial melting of metal powders that can be independently controlled by ionization potential and momentum and thermal energy).

After in situ nucleation (meaning in situ in a reactor or reaction chamber), the solid, substantially solid or semi-solid carbon-based particles exiting the plasma torch can be deposited in an additive, layer-by-layer manner onto a temperature-controlled substrate (such as a drum). The exiting particles can be sprayed onto a particular substrate and bonded to or into the particular substrate. In some cases, a substrate is not used, but rather, the exiting semi-solid particles are grouped to form one or more directional organized, free-standing, self-supporting structures. Unlike standard plasma torches that are limited in operating flow, power, and configuration, the presently disclosed microwave plasma torches include control mechanisms (e.g., flow control, power control, temperature control, etc.) to independently control one or more constituent material temperatures and gas-solid reaction chemistry to produce unique, embossed, highly organized, covalently bonded carbon-metal structures with surprising and extremely high levels of homogeneity.

For illustration, according to various embodiments, the maximum discernible feature size of the uniformly dispersed metal-carbon combination (e.g., defined by the length measured along the longitudinal axis of the "feature") is in the range of about 0.01 nanometers (nm) to 1 micrometer (μm), preferably in the range of about 0.01 nm to about 1 μm, more preferably in the range of about 0.01 nm to about 750 nm, more preferably in the range of about 0.01 nm to about 500 nm, more preferably in the range of about 0.01 nm to about 100 nm, within a certain range, more preferably in the range of about 0.01 nm to about 50 nm, and most preferably in the range of about 0.01 nm to about 10 nm feature size. This is in contrast to non-uniform dispersion, which is characterized by relatively large feature sizes on the order of a few (e.g., 3-5) microns or larger.

The composition of matter may also include a plurality of "aggregates" and/or a plurality of "agglomerates", wherein each aggregate includes a plurality of particles connected together, and each agglomerate includes a plurality of aggregates connected together. In some embodiments, each particle may have a major dimension between 20nm and 150nm. Each aggregate may have a major dimension between 40nm and 10μm. Each agglomerate may have a major dimension between 0.1μm and 1,000μm.

The covetic materials produced by the presently disclosed MW reactor-based technology yield a variety of competitive advantages not otherwise available in current materials or products. One such advantage relates to the inherent scalability and versatility to formulate unique, physically and chemically stable, multifunctional metal-carbon composites that exhibit predictable deformation (in terms of stress, strain, elasticity, or some other determinable physical property) in a variety of configurations and/or architectures such as, but not limited to: (1) dense thin film implants; (2) coatings; (3) thick ribbons; and (4) powdered particles that can undergo subsequent remelting and casting and/or be used to form engineered metal alloy components. The carbon-based metal composite implants and/or coatings and/or strips and/or powdered particles produced by any of the aforementioned dense thin film MW reactors exhibit enhanced physical, chemical and electrical properties compared to existing parent metal alloy formulations.

Materials produced using powders as described above (and/or pellets formed from such powders) enjoy many of the same advantageous physical characteristics and properties of the powders themselves, except that micron-sized materials may not exhibit carbon present in coherent planar layers disposed along the basal planes of the metal lattice. Rather, micron-sized materials (e.g., produced by microwave plasma torch spraying or other suitable techniques described herein (and equivalents as will become apparent to those skilled in the art upon reading such description)) are characterized by heretofore unachievable carbon loadings (e.g., 1.5 wt% to 90 wt%, and any amounts therebetween), uniform/homogeneous dispersion of carbon in the metal matrix, and a lack of carbon aggregates and/or agglomerates at lattice surfaces (e.g., grain boundaries). Aside from that distinction, the final product produced using the powdered material, preferably the powdered covetic material, may exhibit any one or more of the physical characteristics and/or properties (in any combination) of the powdered precursor without departing from the scope of the presently described inventive concepts.

General Embodiment

According to one general aspect, a composition of matter comprises one or more particles, wherein each particle independently comprises a metal lattice having one or more coherent planar graphene layers disposed in the metal lattice.

According to another general aspect, a composition of matter includes an inconel nickel alloy having carbon disposed in a crystal lattice of the inconel nickel alloy.

According to another general aspect, a composition of matter includes a metal lattice having at least about 15 wt % carbon disposed in the metal lattice.

Furthermore, in various embodiments, the aforementioned aspects may include any of the following physical and/or structural characteristics and associated properties. Furthermore, according to different embodiments, these characteristics and/or properties may be included in different combinations or arrangements, but are not limited thereto.

In one aspect, a composition of matter comprises one or more particles, and each particle independently comprises a metal lattice having one or more coherent planar graphene layers disposed therein. Preferably, at least some of the carbon atoms of the one or more coherent planar graphene layers are disposed in interstitial sites within the metal lattice. More preferably, the one or more coherent planar graphene layers are interstitially interlaced between basal planes of the metal lattice. Graphene can exist as a single layer (e.g., "single-layer graphene" or "SLG") or multiple layers (e.g., two layers, three layers, five layers, ten layers, or any number of layers up to fifteen, also referred to herein as "few-layer graphene" or "FLG"). At least some of the carbon atoms of the one or more graphene layers are covalently bonded to metal atoms of the metal lattice, and the covalent bonds between the carbon atoms and the metal atoms are non-polar covalent bonds or include non-polar covalent bonds. In some embodiments, the covalent bonds may consist essentially of or entirely of non-polar covalent bonds. Similarly, the carbon atoms of the one or more graphene layers may be covalently bonded to other carbon atoms of the one or more graphene layers, and according to different embodiments, these covalent bonds may include non-polar covalent bonds, consist essentially of non-polar covalent bonds, or consist entirely of non-polar covalent bonds. Therefore, the one or more particles may include substantially or entirely no polar covalent bonds. Likewise, the metal lattice of each particle may include substantially or completely no ionic bonds. The one or more graphene layers are each preferably substantially free of defects, such that the graphene is "pristine". Preferably, each particle is also characterized by a substantial lack or more preferably a complete lack of carbon aggregates and/or agglomerates at the grain boundaries and/or at the surface of the metal lattice. Due to the innovative processing techniques described herein, the total carbon loading of the particles can range from about 15 wt % to about 90 wt %, with various intermediate loadings also being shown (e.g., in various embodiments, about 20 wt %, about 25 wt %, about 33 wt %, about 40 wt %, about 50 wt %, about 60 wt %, about 75 wt % or up to 90 wt %). Additionally, the particles may be characterized by a diameter in the range of about 20 nm to about 3.5 μm, and/or have a maximum discernible feature size in the range of about 0.1 nm to about 1 μm. In some embodiments, the particles may be pressed into pellets.

According to another aspect, a composition of matter comprises an inconel nickel alloy having carbon disposed in a metal lattice thereof. Preferably, at least some of the carbon is disposed at interstitial sites of the metal lattice, and more preferably, the carbon is substantially uniformly dispersed in the metal lattice. Furthermore, in some embodiments, the grain boundaries of the composition of matter and/or the surfaces of the metal lattice are substantially free of carbon aggregates and/or agglomerates. Thus, the maximum discernible feature size of the composition of matter may be in the range of about 0.1 nm to about 1 μm. At least some of the carbon atoms are covalently bonded to metal atoms of the metal lattice, and the covalent bonds between the carbon atoms and the metal atoms are or include non-polar covalent bonds. In some embodiments, the covalent bonds may consist essentially of or consist entirely of non-polar covalent bonds. Similarly, carbon atoms may covalently bond to other carbon atoms, and depending on the embodiment, such covalent bonds may include, consist essentially of, or consist entirely of non-polar covalent bonds. Thus, the one or more compositions of matter may include essentially or entirely no polar covalent bonds. Similarly, a metal lattice may include essentially or entirely no ionic bonds.

According to yet another aspect, a composition of matter comprises a metal lattice having at least about 15 wt % carbon disposed therein. Preferably, at least some of the carbon is disposed at interstitial sites of the metal lattice, and more preferably, the carbon is substantially uniformly dispersed in the metal lattice. Furthermore, in some embodiments, the grain boundaries of the composition of matter and/or the surfaces of the metal lattice are substantially free of carbon aggregates and/or agglomerates. Thus, the maximum discernible feature size of the composition of matter may be in the range of about 0.1 nm to about 1 μm. At least some of the carbon atoms are covalently bonded to metal atoms of the metal lattice, and the covalent bonds between the carbon atoms and the metal atoms are or include non-polar covalent bonds. In some embodiments, the covalent bonds may consist essentially of or consist entirely of non-polar covalent bonds. Similarly, carbon atoms may covalently bond to other carbon atoms, and depending on the embodiment, such covalent bonds may include, consist essentially of, or consist entirely of non-polar covalent bonds. Thus, the one or more compositions of matter may include essentially or entirely no polar covalent bonds. Similarly, a metal lattice may include essentially or entirely no ionic bonds.

In various embodiments of the foregoing aspects, the metal lattice may include one or more metals selected from the group consisting of aluminum, copper, iron, nickel, titanium, tungsten, chromium, molybdenum, cobalt, manganese, niobium, and combinations thereof. Thus, the metal lattice may be characterized by a crystal structure such as face-centered cubic (FCC), body-centered cubic (BCC), or hexagonal close-packed (HCC). In addition, the metal lattice may include about 15 wt % to about 90 wt % carbon (e.g., about 20 wt %, about 25 wt %, about 33 wt %, about 40 wt %, about 50 wt %, about 60 wt %, about 75 wt %, or up to 90 wt %) in various embodiments. The carbon is preferably present at interstitial sites of the metal lattice. In some methods, the metal may be present in alloy form. For example, in particularly preferred methods, the metal is in the form of one or more Inconel nickel alloys, such as Inconel 600, Inconel 617, Inconel 625, Inconel 690, Inconel 718 and/or Inconel X-750. More preferably, the Inconel nickel alloy is a superalloy.

Overview

The disclosure herein describes the integration of low dosage nanofiller carbon-based materials such as graphene, which is known for its intrinsic structural properties such as high aspect ratio and "2D" planar geometry, with metals. Graphene possesses amazingly good mechanical, physical, thermal and electrical properties due to its in-plane ^sp2C =C bonding (resulting in 2D planar geometry). Therefore, graphene would be an ideal reinforcement for metal matrix composites compared to alternatives such as microfiller polyacrylonitrile (PAN)-based carbon fibers. It is noted that even at low graphene nanoflake content (loading), the 3D network was formed to have anisotropy (referring to an object or substance with different values of physical properties when measured in different directions), which resulted in significantly improved thermal and electrical conductivity as well as mechanical characteristics.

Challenges encountered in using carbon nanofillers in metal matrix composites include difficulty in dispersion due to poor wettability (the ability of a liquid to maintain contact with a solid surface due to the interaction between molecules when the two are brought together; the degree of wetting (called wettability) is determined by the balance of forces between adhesion and cohesion). The increased surface area presented by the nanofillers causes the particles to cluster and entangle due to van der Waals forces between carbon atoms. Aggregation of nanofillers in metal matrix composites can lead to the formation of undesirable cracks and pores, which can ultimately compromise the structural integrity of the resulting material, leading to premature failure under high load or performance conditions.

Although many processing methods, such as those known as powder metallurgy, hot rolling, casting, and additive manufacturing, have been (and are currently possible) used to produce metal matrix composites, challenges remain for uniformly dispersing nanofillers. Damage to the nanofillers caused by stresses applied during consolidation and undesirable or uncontrollable chemical reactions with the matrix at high temperatures during sintering and casting are some examples of challenges faced when trying to achieve nanofiller dispersions.

The defect-free basal plane of graphene exhibits exceptionally favorable chemical stability compared to the sides and ends of graphene sheets, which may more readily interact with metals to form carbides (thermodynamically favorable based on Gibbs free energy). However, during processing, defects may be easily formed in the basal plane, leading to carbide formation and adversely affecting composite properties. Therefore, relatively harsh processing conditions such as high temperature and high pressure may adversely affect the quality of the interface between the carbon nanofiller and its surrounding metal-based matrix. Specifically, high temperature and high pressure may adversely affect wettability, structural integrity, may deleteriously affect carbide formation, and may also induce other detrimental interfacial reactions.

An alternative process called covetic (described earlier) has been successfully used to incorporate carbon nanofillers into metal matrices. In covetic-related processes, it has been shown that networks of graphene "ribbons" and nanoparticles are formed within liquid metals using an applied electric field, and that the networks exhibit remarkable stability within the metal matrix, even after remelting. Accordingly, the composite structures conduct heat and electricity more efficiently than the parent metal.

Uniform dispersion

Since one of the challenges of incorporating graphene into a metal matrix is achieving uniform dispersion, covetic processing overcomes this problem by concomitantly exfoliating and wetting graphene ribbons and/or particles (either from the carbon electrode or from decomposition of carbon additives) in an applied electric field. Impurities such as oxygen and hydrogen can be managed via redox reactions at the particle surface, provided that there is an appropriate induced voltage at the surface to promote wetting/dispersion. The challenge is one of controlling the structural integrity and uniformity of the graphene ribbons and/or particles (e.g. uniformity with respect to size, defects, etc.), as well as controlling the chemical reactivity with metals at high temperatures, and controlling the distribution of particles in the bulk of the melt and at the surface.

Additional complexity

While the fundamental modes of energy conduction in metals (both thermal and electrical) can be (at least partially) carried out by electrons and controlled by the crystallinity and impurities of fillers such as graphene, to enhance the thermal conductivity of metal matrix composites (where conduction is via phonons in graphene), a certain degree of matching and/or coherence with the metal lattice (additionally or alternatively referred to as a scaffold, matrix or structure) is also required (e.g., bulk-bonded nanoscale carbon) or a minimum sheet spacing (e.g., proximity or network) threshold is required for conduction between sheets (e.g., graphene would need to be a monolayer or just a few layers and tens of nanometers in length). However, with respect to strengthening metal matrices, for adequate load transfer (note that for maximum load transfer, the length of graphene can be greater than ~0.5 μm), the graphene may need to be chemically (or in some cases, physically) bonded to the matrix. In addition to solid solution strengthening relying on coherent and/or semi-coherent elastic strain between the carbon (graphene) nanofiller and the metal lattice, discrete graphene nanoparticles can act as a barrier to dislocation stacking or pinning at grain boundaries (e.g., Hall et al., 2005). Petch) grain refinement refers to a method of strengthening a material by changing its average crystallite (grain) size; the grain refinement is based on the observation that grain boundaries are impassable boundaries for dislocations and that the amount of dislocations within a grain can affect the way stresses are formed in adjacent grains, which will ultimately activate dislocation sources and thus enable deformation to occur in adjacent grains; therefore, by changing the grain size, the amount of dislocations accumulated at the grain boundaries and the yield strength can be affected, both of which can improve mechanical performance.

Likewise, due to its 2D nature and high surface area, graphene can be oriented along regions at grain boundaries in addition to being aligned along slip planes within the metal structure. Whether the property of interest is chemical, mechanical, thermal, or electrical, the greater the alignment and matching (at the atomic level) of the crystal structure of the nanofiller with the surrounding metal matrix, the greater the enhancement and stability of the properties of the metal matrix composite structure.

Fundamentally, whether carbon grows at the metal surface (heterogeneous) or precipitates out of solution in the melt (homogeneous) depends on the solubility of carbon in the metal (according to the binary phase diagram shown on the right side of Figure 10). The solubility of carbon in pure transition metals (in general, and in many pure metals) is low near the melting point of the metal, but increases with increasing temperature to well above the melting point of the metal (e.g., up to 2,000°C and above). The solubility of carbon in nickel (e.g., near the hypereutectic point of about 2.5%) is one of the higher solubilities of carbon in pure metals. It should be noted that the addition of interstitial impurities (such as oxygen, boron, or nitrogen) or substitutional atoms to the metal may affect (e.g., potentially increase) the solubility of carbon. It has been demonstrated that the higher the solubility of carbon in the metal or the higher the temperature of the molten metal, the thicker the carbon deposits at the metal surface as the metal cools and solidifies. It is noted that the solubility of carbon is higher near the free surface, which in combination with the interfacial energy of the liquid-air interface favors the precipitation of solid carbon at the metal melt-air interface. Apparatus and techniques for operating the apparatus to overcome the problems associated with this phenomenon are described in connection with the accompanying drawings and corresponding discussion.

Definition and Use of Diagrams

Some of the terms used in this specification are defined below for ease of reference. The terms presented and their respective definitions are not strictly limited to these definitions—a term may be further defined by the use of the term in this disclosure. The term "exemplary" is used herein to mean used as an example, instance, or illustration. Any aspect or design described herein as "exemplary" is not necessarily to be interpreted as being better or advantageous than other aspects or designs. Rather, the use of the word exemplary is intended to present the concept in a concrete manner. As used in this application and the attached application patent scope, the term "or" is intended to represent an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clearly seen in the context, "X adopts A or B" is intended to represent any one of the natural inclusive arrangements. That is, if X employs A, X employs B, or X employs both A and B, then "X employs A or B" is satisfied in any of the foregoing situations. As used herein, at least one of A or B means at least one of A or at least one of B, or at least one of both A and B. In other words, the phrase is disjunctive. The articles "a" and "an" used in this application and the appended claims should generally be interpreted as meaning "one or more" unless otherwise specified or it is clear from the context that they are intended to be in the singular.

Various embodiments are described herein with reference to the accompanying drawings. It should be noted that the drawings are not necessarily drawn to scale and that elements of similar structure or function are sometimes represented by similar drawing labels throughout the drawings. It should also be noted that the drawings are intended only to facilitate the description of the disclosed embodiments—the drawings do not represent an exhaustive treatment of all possible embodiments and are not intended to impose any limitations on the scope of the claims. In addition, the embodiments shown do not necessarily depict all aspects or advantages for use in any particular environment.

Aspects or advantages described in conjunction with a particular embodiment are not necessarily limited to that embodiment and may be practiced in any other embodiments, even if not so described. References to "some embodiments" or "other embodiments" in this specification refer to specific features, structures, materials, or characteristics described in conjunction with that embodiment being included in at least one embodiment. Therefore, the phrases "in some embodiments" or "in other embodiments" appearing in different places in this specification do not necessarily refer to the same one or more embodiments. The disclosed embodiments are not intended to limit the claims.

Description of Exemplary Implementation Methods

FIG. 1A is a comparative table 1A00 showing two different covetic material forming techniques 102 and exemplary materials produced by applying each of the covetic material forming techniques.

In the case of the known metal melting method 103 for producing covetic materials, solid carbon is added to a metal melt. The known metal melting technique is governed by the kinetics of carbide formation and interdiffusion across a solid-liquid (e.g., carbon-metal) interface under an applied electric current, which provides additional energy to overcome the stacking disparity energy between carbon atoms and metal atoms. As such, the known metal melting technique for forming covetic processing is not significantly different from other composite material processing methods (such as powder metallurgy and/or hot rolling), which involve consolidating second phase particles into a metal matrix. These known composite material processing methods face many challenges in terms of dispersion and/or distribution, reactivity, and variability of material properties. Furthermore, covetic processing is known to rely on batch processing and often results in inconsistent conversion yields and wide variations in the resulting properties.

As depicted in image 105, when conventional metal melting methods 103 are used, the resulting material includes many carbon aggregates and/or agglomerates, particularly at grain boundaries and/or at the surfaces of the metal lattice. This in turn: (1) limits the role of carbon in reinforcing the lattice; and (2) limits the tunability of the surface morphology of the surface functionalization. In comparison, when the presently disclosed techniques are used, the resulting material exhibits nearly uniform homogeneity (e.g., no or substantially no aggregates and/or agglomerates, particularly at grain boundaries and/or at the surfaces of the lattice), which is caused by the carbon being evenly dispersed in the lattice. This is shown in homogeneity image 106.

The covetic material, as depicted in the homogeneity image 106, may be characterized by a number of desirable material properties 108, such as homogeneity, high carbon loading, low carbon content at the surface, etc. These properties are extremely desirable material properties that are not exhibited by materials formed using conventional metal melting methods 103. Therefore, improved methods that overcome the shortcomings of conventional metal melting methods 103 are sought.

One such improved method involves a plasma torch method 104. The application of the plasma torch method results in a consistent yield of covetic materials, thereby overcoming the yield disadvantages of conventional metal melting methods. In addition, the covetic material produced by the application of the plasma torch method has the above-mentioned improved mechanical properties, improved thermal properties, and improved electrical properties, thereby overcoming the disadvantages of the materials obtained by conventional metal melting methods.

Improved methods

As shown, the plasma torch process 104 can be configured to use an introduced input material (referring to a carbon-containing feedstock material provided in gaseous form, such as methane, and powered by applying MW energy directed through the methane gas, etc.). However, by dissociating a carbon-containing gas (such as methane or other hydrocarbon source) at high temperature, self-limiting monolayers of carbon - particularly pristine graphene - can be grown onto or into a metal (such as copper, gold, zinc, tin, and lead) lattice. The number of monolayers depends at least in part on the solubility of carbon in the metal. The growth kinetics, bonding, and final structure of graphene films on metal substrates depend on the valence electrons and symmetry (closely packed planes) of the metal. Similarly, metals can grow on carbon, nucleating and growing preferentially at defect sites of carbon or also at selective oxygen or hydrogen termination sites. Alternating stacks of monolayers of carbon and metal can then be made to achieve the reinforcing properties of graphene-enhanced metal composite structures.

Using a microwave plasma reactor, pristine 3D few-layer graphene particles can be continuously nucleated and grown from a hydrocarbon gas source. In addition, by adding selective elements to the plasma gas stream, these selective elements can be incorporated into the 3D graphene particle scaffold. The microwave plasma reactor process provides a unique reaction environment in which gas-solid reactions can be controlled under non-equilibrium conditions (such as chemical reactions can be independently controlled by ionization potential and momentum and thermal energy). Reactants can be inserted into the plasma reactor region in the form of solids, liquids, or gases to independently control the nucleation and growth dynamics of unique non-equilibrium structures (such as graphene on metal and metal on graphene).

For example, to create nanoscale integrated graphene-metal composites, fine nanoscale metal particles can be introduced into a microwave plasma torch along with a hydrocarbon gas such as methane. The methane dissociates into hydrogen and carbon (such as C and _H2 using the ideal energy of the microwave plasma), and the carbon can then nucleate and grow ordered graphene onto the semi-molten surface of the metal particles. Non-equilibrium energy conditions can be created by adjusting the process conditions to independently control the temperature of the metal relative to the carbon reactivity and delivery to the metal surface. At controlled low energies, the ionized hydrogen (or other ions) can be used to impact/splash the growing graphene-metal surface without disrupting the structure of the graphene-metal composite. This then promotes further growth of alternating graphene-metal layers. In addition, depending on the residence time and energy in the plasma reaction zone, metal-graphene structures with specific properties can be produced, which are retained when the metal-graphene structure is sprayed onto the substrate at a controlled temperature and then quickly cooled. The formation of metal-graphene structures with controlled energy in the plasma and the control of the substrate temperature provide independent control of the energy conditions during the entire evolution of these covetic materials.

Graphene can be applied (and/or deposited) onto a layer of metal or metal-containing material by "sputtering" (the phenomenon in which microscopic particles of a solid material are ejected from its surface after the solid material itself has been bombarded with energetic particles from a plasma or gas; the fact that sputtering can act on very fine layers of material is often exploited in science and industry - in science and industry, sputtering is used to perform precision etching, analytical techniques, and to deposit thin film layers in the manufacture of optical coatings, semiconductor devices, and nanotechnology products). When used with the MW plasma reactors currently discussed, the sputtering thus described can be controlled by controlling the residence time and energy in the plasma reaction zone to promote the growth of alternating graphene-metal layers organized in coherent planes of atoms in a regular (e.g., crystalline) configuration. The crystal structure is preserved when the graphene-metal layer is rapidly quenched (in materials science, quenching or rapid/sharp quenching refers to the controlled rapid cooling of a workpiece in water, oil or air to obtain certain material properties; quenching is a heat treatment that prevents or controls the occurrence of undesirable low-temperature processes such as phase changes by reducing the time window during which such undesirable reactions are thermodynamically favorable and kinetically feasible; for example, quenching can reduce the grain size of both metals and plastics, thereby increasing their hardness) onto a cooler substrate. As described, rapid quenching is used to essentially "freeze" (meaning to remain in a substantially solid state, not just the traditional phase change definition from liquid to solid) the graphene into the metal in the desired crystalline configuration formed in the plasma reactor. The resulting material is very uniform in homogeneity both within and at the surface. This very uniform homogeneity can be used to distinguish it from materials that have been formed using the metal melting process 104. The reason is that the metal melting process 104 cannot control the ion energy independently of thermal energy. More specifically, because the metal melting process 104 cannot achieve the desired higher ion energy independently of thermal energy, the temperature in the metal melting reactor may be too high to cause the graphene-metal layers to be organized in atomically coherent planes in the desired crystalline configuration.

Therefore, when using the metal melting method 104, the desired crystal configuration of the graphene-metal never occurs and is therefore not retained when the graphene-metal layer is quenched onto a cooler substrate. Instead, when using the metal melting method 104, undesirable carbon precipitation occurs (e.g., carbon precipitates out of the melt), which in turn leads to undesirable formation of aggregates and/or agglomerates, which in turn leads to inhomogeneity in the resulting composition. This inhomogeneity in the resulting composition may result in less than ideal chemical and/or physical (mechanical) properties of the resulting composition, including but not limited to premature mechanical failure.

FIG1B shows a high-resolution transmission electron microscopy image 114 and a high-resolution energy dispersive spectroscopy x-ray image 116. For convenience, the homogeneity image 106 of FIG1A is also shown here.

As depicted in this set of exemplary images, the carbon is evenly distributed in the metal lattice. This is emphasized in the high-resolution transmission electron microscopy image 114. In addition, the extremely high carbon loading in the metal lattice is clearly shown by the high-resolution energy dispersive spectroscopy x-ray image 116. In this example, the carbon loading forms about 60% of the entire copper-carbon lattice. This is shown in the high-resolution energy dispersive spectroscopy x-ray image 116. In this particular image, the darker areas are carbon, and the lighter areas (appearing as dots) are copper.

As can be seen from the images, and specifically from the pattern of high resolution energy dispersive spectroscopy x-ray image 116, the carbon and the parent metal (such as copper in this case) are uniformly dispersed. As shown, the uniform lattice-level dispersion exists at the surface, and in addition, the uniform lattice-level dispersion also exists deep in the parent metal. Figures 20A1, 20A2, and 20B provide additional images of covetic materials, which are followed by a discussion of (1) material evolution processes, (2) plasma spray torch equipment, and (3) various configurations of plasma spray torches.

In one use scenario, the covetic material in Figure 1B can be fabricated using a tunable microwave plasma torch that produces integrated graphene-metal composite films at high rates and volumes. A specific fabrication process during which graphene is grown onto small molten metal particles is now briefly discussed.

FIG. 2 depicts a fabrication process 200 for growing graphene onto small molten particles. Alternatively, fabrication process 200 or one or more variations thereof may be implemented within the context of the architecture and functionality of the embodiments described herein. Fabrication process 200 or any aspect thereof may be implemented in any environment.

One possible approach is to use a "non-equilibrium energy" microwave plasma torch to provide non-equilibrium control of the metal temperature independently of the generation of carbon. This plasma torch energy is then directed to the surface of molten and/or semi-molten metal particles. This technique allows time for growth to occur on the melt. The growth on the melt (or semi-molten or core material) generated in the torch will flow out through the main plasma plume to the metal surface on which growth is to occur and then rapidly quenched. This technique provides a means for growing thick films that can be grown into homogeneous ingots when layered and/or grown into or onto component parts that are subsequently processed or remelted into applications.

Additionally, Figure 2 is presented to demonstrate the effects of independently controlling the constituent material temperature and gas-solid reaction chemistry when growing graphene onto small molten particles. Figure 2 shows the evolution of covetic material through several fabrication processes; and presents the process used in the formation of plasma torch-based covetic materials.

As shown, semisolid particles exiting the plasma torch can be deposited in an additive, layer-by-layer manner onto a temperature-controlled substrate. Unlike standard plasma torches, which are limited in operating flow and power control and other configurations, the microwave plasma torch discussed can be operated to independently control the constituent material temperature and the gas-solid reaction chemistry.

As can be seen from the above disclosure, microwave plasma sources can produce (for example): (1) higher plasma density; (2) ion energy with a narrower ion energy distribution; and (3) improved coating properties. This is at least partially due to improved power coupling and (electromagnetic energy) absorption at 2.45 GHz. The typical electron temperature related to pressure is on the order of 1 eV to 15 eV, resulting in a plasma density of >10 ¹¹ cm ^-3 . Such low electron temperatures are not only beneficial in controlling plasma chemistry, but also in limiting ion energy, where the ion energy of argon-based coaxial microwave plasma is typically in the range of 5 eV to 80 eV. Because of the narrow plasma sheath formed using these high density plasmas, collisional broadening of the ion energy distribution is prevented, resulting in a sharp ion energy distribution that supports fine control of certain film deposition processes. In addition, by applying pulsed power to the microwave plasma, non-equilibrium energy can be created and controlled. During the application of microwave energy, power is delivered to the entire volume of the plasma to be formed, so energy is accumulated in a stepwise collisional energy mode.

The foregoing discussion of FIG. 2 includes a technique for applying microwave energy power, which technique is further disclosed in detail below.

FIG3 depicts a plasma energy state diagram 300 showing how a pulsed microwave energy source may be used to grow graphene onto small molten particles.

Due to improved power coupling and absorption at 2.45 GHz, microwave plasma sources have the potential to achieve higher plasma density, ion energy with narrower ion energy distribution and improved coating properties. Typical pressure-dependent electron temperatures are on the order of 1 eV to 15 eV, resulting in plasma densities > 10 ¹¹ cm ^-3 . Such low electron temperatures are beneficial not only in controlling plasma chemistry, but also in limiting ion energies, where ion energies for coaxial microwave plasmas based on argon are typically in the range of 5 eV to 80 eV. Because of the narrow plasma sheath formed using such high density plasmas, collisional broadening of the ion energy distribution is prevented, resulting in a sharp ion energy distribution, which is necessary for fine control of some film deposition processes. In addition, by using pulsed power delivered to the microwave reactor, plasma non-equilibrium energy can be generated and controlled. During the application of microwave energy, power is delivered to the entire volume of the plasma to be formed, so that energy is accumulated in a stepwise collisional energy mode.

Once the initial plasma is formed in a large portion of the volume, the delivery antenna at the maximum energy continues to increase in a highly localized manner. The plasma density decreases slightly nearby until the plasma contracts. Additional details regarding a general method for making and using a pulsed microwave energy source are described in U.S. Patent Publication No. 10,332,726, published on June 25, 2019, which is hereby incorporated by reference in its entirety.

Figure 3 shows that the initial energy of the plasma is much higher in the non-equilibrium state until the plasma contracts to a much lower stable temperature. More specifically, the plasma energy state diagram depicts the transition from the initial high energy non-equilibrium state to the lower energy stable equilibrium state. Once the initial plasma is formed, the energy of the delivery antenna at the maximum value will continue to increase in a highly localized manner until the plasma contracts and is lost in the rest of the chamber due to energy shielding.

The pulsed microwave energy source can be controlled to optimize the electron temperature used to grow graphene onto small molten particles. This is particularly effective at pressures >>20 Torr. The chamber environment must be controlled to ensure that the plasma chemical dissociation is homogeneous and the material coating is also homogeneous.

As shown in Figure 3, the energy curve shows that the initial energy is high and after a period of time it shrinks to a lower level, where it stays until the power is removed. The plasma extinguishes and, after restarting, follows the energy cycle again. By shortening the time between the initial plasma ignition and when it reaches stability, the plasma is primarily retained in the body of the system where a more homogeneous dissociation of the material can occur. The shortening of the time between the initial plasma ignition and when it reaches stability can be accomplished by controlling the frequency and duty cycle of the pulses.

A technique for controlling the temperature of electrons in a pulsed microwave reactor is shown and described with respect to FIG. 4 .

FIG. 4 depicts an electronic temperature control technique 400 for growing graphene onto small molten particles. Alternatively, the electronic temperature control technique 400 or one or more variations thereof may be implemented in the context of the architecture and functionality of the embodiments described herein. The electronic temperature control technique 400 or any aspect thereof may be implemented in any environment.

Figure 4 shows the state of growing a few layers of graphene onto molten nano-sized particles rather than mixing carbon into the bulk of the molten slurry. Specifically, the figure is presented with respect to its contribution to controlling the plasma temperature by controlling the microwave pulse frequency.

Plasma temperature control by controlling pulse frequency

As depicted in Figure 3 above, the energy curve shows that the initial energy is high and after a period of time it shrinks to a lower level where it stays until the power is removed. The plasma extinguishes and upon restarting, the energy cycle is followed again. By shortening the time between initial plasma ignition and reaching stability, the plasma is primarily retained in the bulk of the system where a more homogeneous dissociation of the material can occur.

As shown in Figure 4, the effect essentially depends on the timing of the on/off cycle of the microwave energy source. By controlling the pulse frequency, optimal chemical dissociation and uniform coating can be produced. In addition, by setting the pulse frequency, the average temperature of the plasma can also be controlled.

Plasma temperature control in microwave plasma torch

The integrated microwave plasma torch discussed herein is used to address the formation of integrated second phase carbon-metal composite structures having enhanced mechanical, thermal and electrical properties compared to existing metal alloys and known composite material processing methods. In addition, the microwave plasma torch can be used to form carbon-metal composite coatings and particles directly onto high value asset components. In addition, the aforementioned method and apparatus meet many clean energy goals related to improved power distribution and efficient transformer and heat exchanger performance.

Microwave Plasma Torch Practical Application

Using integrated microwave plasma torch technology, materials can be deposited and/or formed economically (i.e., cost-effectively) at a faster rate and can be applied in a variety of different configurations. Donors of this technology include various energy production industries, particularly related to the transmission and storage transportation industry, the military equipment industry, and many other manufacturing industries. As a specific practical application example, the metal surface of an aircraft can be treated by plasma spraying to produce a covetic material at the metal-air interface. The metal surface thus becomes impervious to corrosion. In addition, the carbon atoms close to the surface allow other materials to chemically bond to the carbon atoms and/or adhere to the surface. The aforementioned other materials that can chemically bond to the carbon atoms can be selected based on the requirements that arise in various practical applications.

As another specific practical application example, the metal surfaces of air vehicles (such as airplanes, helicopters, drones, projectiles, missiles, etc.) can be treated by plasma spraying to produce a covetic material coating that acts as an infrared shield (such as a detection countermeasure).

FIG. 5 shows a dual plasma torch apparatus 500 for growing graphene onto small molten particles. As an option, the dual plasma torch apparatus 500 or one or more variations of any aspect thereof may be implemented in the context of the architecture and functionality of the embodiments described herein. The dual plasma torch apparatus 500 or any aspect thereof may be implemented in any environment.

The equipment set-up shown uses: (1) a metal plasma spraying torch for supplying molten metal to the surface of a heated substrate (Al, Cu, Ag, etc.); and (2) a microwave plasma torch for delivering ionized carbon and plasma radicals to the molten surface to enable covetic growth onto the molten metal.

The system is inserted into an inert gas environment or a controlled atmosphere chamber to provide better control over the oxidation of the material. In one embodiment, the setup and operation of the torch in FIG. 5 are shown in Table 1, the details of which are discussed below.

Step D1: Identification and selection of reactant materials

Any amount of metal can be plasma sprayed simultaneously with the metastable carbon material to form a nanocarbon-metal composite structure. When forming 2D graphene at concentrations above the thermodynamic solubility limit, different metals with high electrical and thermal conductivity can be used. In some cases, two different metals are selected, each of which has a different carbon solubility limit and/or a different melting point and/or a different density and/or a different crystal structure.

Step D2: Microwave and " Standard " Plasma Spray Torch Selection, Modification and Validation

The apparatus of FIG. 5 may (in certain embodiments) be substantially comprised of "standard" off-the-shelf plasma spray and microwave plasma torches. Having two torches allows for two distinct processing steps, namely: (1) initial melting of the metal; and (2) nucleation/growth of graphene flakes from a hydrocarbon source. Each of the two torches may be controlled independently of the other.

As shown in FIG5 , the two torches are juxtaposed for parallel or sequential operation. Specifically, a microwave plasma with a low electron temperature and high electron density can be used to optimize graphene formation (including carbon supersaturation and nucleation rate at critical values), while a standard plasma spraying torch can be used to heat the metal powder/particles to a molten or semi-molten state and then accelerate the particles (and nucleated ionized carbon/graphene) toward the substrate. The two independent flow streams can be coordinated to achieve fine-scale graphene growth on the surface of the semi-molten particles. In some cases, the dual torch configuration includes components for maintaining an inert atmosphere (such as a blanket gas) at or near the outlet stream of the torch and in and around the impact zone at the substrate surface. This arrangement is advantageous to minimize or preferably prevent the inclusion of atmospheric gases in the composition of matter (such as oxygen, nitrogen, water vapor, etc.) which may adversely affect the bonding between carbon and metal atoms, as will be understood by those skilled in the art. Therefore, in certain embodiments, the dual torch system is configured to be inserted into a fully controlled inert gas environment (such as a chamber) to provide effective control over the oxidation of the material.

Step D3: Basic principles and definitions of plasma processing parameters

The reactants (such as hydrocarbons) and inert gases and flows are selected to ensure plasma stability and to ensure control of nucleation and growth processes within the plasma (such as supersaturation and thresholds for a given gas mixture and flow rate). The acceleration rate and temperature of the metastable carbon are controlled during its transition from the plasma to the substrate. Accordingly, the process conditions of the standard plasma spray torch are set to produce a solidified film on which the carbon can impinge and react. The surface temperature and local gas phase environment are controlled to promote the interaction and growth of the metastable carbon phase.

Step D4: Operate the dual (metal and microwave) plasma torches

Various processing window parameters of the metal and microwave plasma torches are configured to be controlled independently or in combination with one another in certain embodiments. The processing window of the integrated carbon-metal formation is characterized before, during, and after operation of one or more of the metal and microwave plasma torches (referred to herein as "dual plasma torches"). In addition, one or more parameters or combinations of parameters are selected, the deposition of the carbon-metal is observed, and the as-deposited samples can be characterized with respect to various distinguishing factors, including (but not limited to): morphology (such as using scanning electron microscopy (SEM)), structure (such as by x-ray diffraction (XRD) and Raman spectroscopy), and/or physical and chemical composition using any technique known in the art.

FIG6 shows a pulsed microwave plasma spray torch apparatus 600 that can be adapted for growing graphene onto small molten particles. As an example, one or more variations of the pulsed microwave plasma spray torch apparatus 600 (or any aspect thereof) can be implemented in the context of the architecture and functionality of the embodiments described herein. The pulsed microwave plasma spray torch apparatus 600 (or any aspect thereof) can be implemented in any environment.

In this configuration, a transverse electric field (TE) microwave energy power element may be coupled to (or, in some embodiments, substantially penetrate) the central dielectric tube to propagate microwave energy into and through the central dielectric tube. The gas supplied to the central region (in this example) may be a hydrocarbon gas, such as methane, that absorbs microwave radiation. Metal powder is supplied (carried by a substantially inert carrier gas) to be heated by a combination of plasma derived and applied thermal energy within the main body (or main chamber) of the pulsed microwave plasma spray torch apparatus 600. When exposed to this energy, the metal powder melts when the melting temperature is reached to produce a viscous flowable liquid material or droplets (which may contain semi-solid materials), or any other conceivable dispersion (depending largely on the accompanying melting conditions).

As the hydrocarbon gas decomposes into its component elemental species, carbon radicals nucleate on the exposed surface of the molten metal droplet. The combination of microwave energy tuning settings and thermal plume temperature settings allows for a temperature differential between the melting temperature and the plasma decomposition/ionization temperature in the central region of the pulsed microwave plasma spray torch apparatus 600. Non-equilibrium conditions (referring to temperature, pressure, etc.) within the central chamber or region of the plasma spray torch apparatus allow (or otherwise promote) internal lattice placement of graphene/carbon, while rapid quenching produces conditions favorable for covetic material growth.

As understood herein, internal lattice placement refers to the positioning of the resultant lattice structure of, for example, a carbon material such as graphene within the lattice structure of an input metal such that individual carbon and metal atoms are at least partially aligned. For example, internal lattice placement includes situations where one or more graphene layers (preferably coherent planar layers) such as single layer graphene (SLG) or few layer graphene (FLG) are interstitially juxtaposed between basal planes of a metal lattice and/or interstitially interlaced between basal planes of a metal lattice. Internal lattice placement also includes embodiments where other carbon-based compounds (such as three-dimensional graphene, carbon nano-onion (CNO), graphene nanoribbons, carbon nanotubes, graphene superlattices, and their equivalents as will be understood by those skilled in the art) are interstitially juxtaposed between basal planes of a metal lattice and/or interstitially interlaced between basal planes of a metal lattice. Likewise, regardless of the specific synthetic lattice structure of the carbon-based compound, the primary characteristic of the internal lattice placement is that the individual carbon and metal atoms are at least partially aligned. Diagrams showing internal lattices in which the carbon lattice and the metal lattice are oriented such that the carbon atoms and the metal atoms are at least partially aligned are presented in Figures 8A-B, Figure 12, Figure 26C, and Figure 26D and the corresponding written descriptions below.

Internal lattice placement thus refers to the spatial arrangement of carbon and metal atoms in the crystal lattice and is distinguished from chemical and/or ionic bonding, but according to various embodiments, the presently described inventive compositions of matter may additionally include properties such as nonpolar covalent bonding between individual carbon atoms within the composition of matter and/or nonpolar covalent bonding between individual carbon atoms and metal atoms within the composition of matter.

Preferably, the composition exhibiting an internal lattice arrangement is characterized by a substantial lack of polar covalent bonding between individual carbon atoms and a substantial lack of polar covalent bonding between carbon atoms and metal atoms. More preferably, the inventive concepts described herein are characterized by a substantial lack of ionic bonding within the metal lattice.

As those skilled in the art will appreciate, polar covalent bonds, nonpolar covalent bonds, ionic bonds, and metallic bonds each have unique distinguishing characteristics and corresponding electronic and chemical properties.

After the complete transfer of bonding electrons from one atom to another, an ionic bond results. The resulting positively and negatively charged ions are then electrostatically attracted. Importantly, ionic bonds rarely have any particular directionality, since they result from the electrostatic attraction of each ion to all surrounding ions of the opposite charge. Ionic compounds generally have high melting temperatures, high boiling temperatures, are brittle (low mechanical strength), and can conduct electricity in the molten state or in aqueous solution.

In metallic bonding, the bonding electrons are delocalized on the lattice of atoms. In metals, each atom donates one or more electrons that reside between many atomic centers. The free movement of delocalized (or "free") electrons is therefore responsible for important properties of metals, such as high electrical and thermal conductivity. Notably, the innovative compositions of matter described herein having carbon dispersed in a metal lattice and having substantial covalent bonding between carbon atoms of the lattice and metal atoms may be characterized in that all or substantially all (e.g., at least 90%, at least 95%, at least 98%, at least 99%, etc.) of the electrons are involved in such covalent bonding, thereby altering the electrical and/or thermal conductivity of the composition.

Although both polar and nonpolar covalent bonding involve the sharing of electrons, compounds that include polar covalent bonds are characterized by the unequal sharing of electrons between the bonding partners. For example, in hydrogen chloride, the chlorine atom has a higher electronegativity than hydrogen, and exhibits a stronger attraction for the electron. Therefore, the "shared" electron is more strongly associated with the chlorine atom, resulting in a partial negative charge on the chlorine and a partial positive charge on the hydrogen (thus creating a dipole in the HCl molecule). In water, the bond between each hydrogen atom and an oxygen atom is similarly characterized due to the greater electronegativity of the oxygen. This results in a dipole moment between each hydrogen atom and the oxygen atom, and due to its curved shape, a total dipole throughout the water molecule. However, not all compounds that exhibit nonpolar covalent bonding exhibit an overall dipole. Tetrachloromethane has four chlorine atoms bonded to a central carbon and equidistantly spaced from each other. Although each carbon-chlorine covalent bond is nonpolar, the spatial arrangement of the molecule cancels out the overall bond moment, resulting in a molecule with zero net polarity. Similarly, the rectilinear shape of carbon dioxide cancels out the dipole moment exhibited between each oxygen atom and the central carbon, resulting in a molecular structure with no net dipole moment.

In any case, in the presence of an electric field, the atoms and/or electron clouds involved in the polar covalent bonds can be deflected, thereby causing a polarization that is aligned with the electric field. This phenomenon can give the corresponding compound an energy storage capacity and contribute to the capacitance of the material composition. Compounds that exhibit polar covalent bonding are particularly small molecules or molecules that have a majority of polar covalent bonding (e.g., in various embodiments, at least 10%, at least 20%, at least 25%, at least 50%, etc.) characterized by melting and boiling temperatures lower than compounds that exhibit ionic bonding (again, particularly small compounds and compounds that exhibit a majority of ionic bonding), but higher than compounds that exhibit non-polar covalent bonding (again, particularly small compounds and compounds that exhibit a majority of non-polar covalent bonding). Compounds that exhibit polar covalent bonding may or may not exhibit electrical conductivity, but are generally less than ionic compounds. Additionally, compounds that exhibit polar covalent bonding (again, especially small compounds and compounds that exhibit a large fraction of polar covalent bonding) are moderately soluble in water (solubility depends on the overall polarity of the compound), but are generally insoluble or only nominally soluble in nonpolar solvents.

In contrast, nonpolar covalent bonding is characterized by the equal sharing of electrons between the bonding partners and, therefore, the lack of any dipole moment therebetween. Compounds that exhibit only (or substantially only) nonpolar covalent bonding between the constituent atoms therefore lack an overall dipole moment and the corresponding properties associated therewith as described above and other properties that will be understood by one of ordinary skill in the art after reading this disclosure. Exemplary, non-limiting compounds that exhibit only (or substantially only) non-polar covalent bonding include graphite, single-layer graphene (SLG), few-layer graphene (FLG), three-dimensional graphene, carbon nano-onion (CNO), graphene nanoribbons, carbon nanotubes (CNT) (single-walled (SWCNT) and multi-walled (MWCNT)), graphene superlattices, etc. as described herein, and their equivalents that will be understood by those skilled in the art after reading this specification.

For example, compounds that exhibit nonpolar covalent bonding (particularly small molecules such as carbon dioxide, molecular hydrogen, methane, etc.) and compounds that do not substantially include polar covalent and ionic bonds are generally characterized by low boiling and melting temperatures and low electrical conductivity. In most compounds that exhibit nonpolar covalent bonding, London dispersion forces control the electronic properties of the compound. However, despite being composed essentially of nonpolar covalent bonds, graphene (and similar compounds that exhibit ^sp2 and/or ^sp3 bonding and/or substantial coordination between electrons due to the physical arrangement and bonding pattern of the molecular structure, as will be known to those skilled in the art after reading this disclosure) exhibits significant electrical conductivity. Similarly, compounds that exhibit nonpolar covalent bonding are generally insoluble or only nominally soluble in water (but may be soluble in nonpolar solvents).

Referring now to FIG. 6 , the single integrated microwave plasma torch of FIG. 6 may be configured and operated as described in Table 2 below, the details of which are described below.

Step S1: Deployment of a single integrated microwave plasma torch

FIG6 depicts a single integrated microwave plasma torch. The torch has the capability to process solid, liquid, and vapor reactant feedstock materials using, for example, a small inert gas or a differentially pumped vacuum for controlling gas flow. The torch can be deployed in any environment, be it a laboratory, research institution, or large-scale industrial enterprise.

Step S2: Operating a single integrated microwave plasma torch to form a graphene-loaded metal composite ( “ covetic ” ) alloy

Microwave energy is delivered in a co-linear waveguide configuration along with a centralized gas feed system for efficient microwave energy absorption. The microwave energy source is used to heat the metal to a semi-molten state. As _CH4 (or other hydrocarbon source) decomposes (to its component species) within the exhaust plume directed into the surface wave plasma gas decomposition tube, carbon radicals can nucleate on the metal droplet surface (e.g., in an organized layer-by-layer manner) via excitation by plasma radicals (directed onto the metal droplets). Tuning of the microwave heat plume temperature and the energy of the plasma allows independent control of the temperature between the melt and the plasma decomposition/ionization occurring within the central region of the pulsed microwave plasma spray torch apparatus 600.

Measure and optimize process conditions. The desired process conditions are controlled by or for the integrated microwave plasma torch to form graphene-loaded metal composites directly in a single-stage or multi-stage plasma reaction torch. The plasma torch can be modulated in different regions of the surface wave plasma to increase the number of resonances (modulations) and optimize the formation of the target metal-carbon structure.

In addition to the process gas ports shown at the depicted locations (e.g., for introducing hydrocarbon process gas 605), additional ports 604 may be provided at different locations. Such additional ports may be used to control how process gases are introduced into the microwave field, and to introduce other process gases. As examples, the process gas may be _SiH4 or _NH3 . In some embodiments, more than one gas input port or more than one particle input port (e.g., one carbon input port and one metal input port) may be included, wherein the locations of the input ports may be positioned in different areas of the plasma torch.

The above settings and conditions, as well as other conditions, are optimized to produce conditions at the substrate surface that enable the impacting particles to consolidate into a film. The as-deposited film is analyzed and characterized according to the method outlined in step S3 below.

Step S3: Verify/characterize the metallic properties of graphene (secondary phase)

Characterization of deposited integrated carbon-metal composite structures is accomplished using several techniques. For example, x-ray photoelectron spectroscopy (XPS) and/or SEM-EDS can be used to determine chemical composition, binding energy (nanoscale carbon detection) and distribution. In addition, energy dispersive x-ray spectroscopy (EDS) and/or SEM and/or Raman spectroscopy and/or XRD can be used to determine morphology and/or measure grain size and structural characteristics. Electrical and thermal properties of the composites as well as tensile strength and modulus can be evaluated using any known technique.

result

The above technology uses a microwave plasma torch to continuously produce metal matrix composites. The process involves material nucleation and formation of growth zones in the plasma, followed by acceleration and collision zones for consolidation of the material onto the substrate. Each zone provides unique control over the synthesis/blending and integration of different materials; that is, the selectivity and unique formulation of alloy particles in the plasma, followed by unique additive processes for controlling consolidation parameters such as porosity, defect density, residual stress, chemical and thermal gradients, phase changes and anisotropy by controlling the momentum (primarily kinetics) and thermal energy during collision on the substrate.

Various materials are selected for use across a wide range of growth dynamics within a plasma operating environment. Specifically, hydrocarbon gas sources having specific carbon-oxygen-hydrogen ratios and solid metal (or metal alloy) particle sources having different carbon solubilities, melting points, and crystal structures can be processed via a pulsed energy plasma torch processing system. In this way, specific plasma processing parameters can be identified for the concomitant initial surface melting of the particles along with the nucleation/or growth and incorporation of 2D graphene and resputtered metal at the metal surface.

After incorporation of graphene into metal from a microwave plasma torch, the as-deposited material/film is characterized with respect to "covetic-like" properties. As an example, these covetic-like properties can be characterized, for example: (1) chemical composition (e.g., for detecting impurities and for detecting carbon form); (2) carbon distribution (e.g., interstitial - referring to the location of carbon atoms or species within the metal matrix or lattice, both intracrystalline and intercrystalline); (3) conductivity; and (4) mechanical strength of the material. Characterization can include a comparison between graphene loading and the unalloyed parent metal. In addition, by way of example only, using a microwave plasma torch, the as-deposited material can exhibit a carbon to metal ratio in the range of about 3% to 90%, inclusive. In some cases, the carbon to metal ratio is in the range of about 10% to about 40%, inclusive. In some cases, the carbon to metal ratio is in the range of about 40% to about 80%, inclusive. In some cases, the carbon to metal ratio is in the range of about 80% to about 90%, inclusive. In some cases, the carbon to metal ratio is greater than 90%, inclusive. The carbon to metal ratio may be affected (or further affected) by parameters or specifications that define the coating process (e.g., temperature, thickness, homogeneity, etc.).

Thus, carbon may be present in amounts that are not achievable using conventional techniques, for example, according to various embodiments, the resulting material may contain greater than about 6 wt% carbon, greater than about 15 wt% carbon, greater than about 40 wt% carbon, greater than about 60 wt% carbon, or up to about 90 wt% carbon. In various embodiments, carbon may be included in the metal lattice in the aforementioned amounts such that all or substantially all of the carbon is incorporated into the metal (or other material) lattice and the grain boundaries/lattice surfaces are substantially or completely free of carbon aggregates and/or agglomerates. In addition, carbon is preferably present/located at interstitial sites of the lattice.

FIG. 7 is a diagram 700 depicting a coating process. The diagram relates to a metal substrate that is subjected to plasma torch spraying of a covetic material, which in turn produces a resultant composite carbon coating. The metal substrate may include any one or more of aluminum, copper, iron, nickel, titanium, tungsten, chromium, molybdenum, cobalt, manganese, niobium, and alloys thereof (e.g., various inconel nickel alloys as described above) or other bulk metal materials. The covetic material may include one or more of carbon, graphene, nano-onions, carbon nanotubes (CNTs), carbide implant materials, etc.

Plasma torch coating is used to coat input material with deposited material and may be operated using pulsed energy. As shown, the material deposited (such as by layer-by-layer sputtering) may be any one or more of carbon, metal (such as listed above), and/or oxides or nitrides.

Several advantages arise from the use of the above-described torches. Chief among these advantages is the scalability and versatility of the process to formulate unique stable metal-carbon composites in a variety of configurations/architectures. These configurations/architectures range from fully dense thin film coatings to thick strips or pellets that are subsequently remelted and cast/formed into engineered metal alloy components. Each of these materials within the above range exhibits unexpectedly good (and desirable) enhanced mechanical, thermal, and electrical properties when compared to existing parent metal alloy formulations. In addition, the tunability of the concentration and distribution of covalently bonded 2D graphene in a metal alloy matrix above the thermodynamic solubility threshold and the layer-by-layer formation in a non-equilibrium plasma environment enable a new class of composite materials that can be engineered to correspond to specific applications and/or to correspond to specific property requirements. Furthermore, this can be accomplished at significantly reduced costs compared to other techniques.

The enhanced mechanical, thermal and electrical properties can be applied to applications that use a large number of copper and aluminum alloys. As examples, such applications include (but are not limited to): wire conductors and high voltage power transmission cables, microelectronics thermal management and heat exchangers, and many applications using thin film conductors such as batteries, fuel cells and photovoltaics. Specifically, the combination of microwave plasma torch processing and the realization of carbon-metal alloy production provides significant energy savings and improved thermal efficiency in the manufacturing process, and reduces electrical losses in the final application performance.

The aforementioned plasma spraying technique describes only one type of method for making covetic materials. Another type involves spraying carbon particles onto small molten metal particles. This type and aspects of this type are shown and discussed with respect to Figures 8A-B, 9, 10, 11, 12, 13, and 14 and the discussion in the figures herein.

8A-B are schematic diagrams depicting a plasma spraying process 800 for spraying carbon particles onto small molten particles. As an option, one or more variations of the plasma spraying process 800 (or any aspect thereof) may be implemented in the context of the architecture and functionality of the embodiments described herein. The plasma spraying process 800 or any aspect thereof may be implemented in any environment.

Plasma spraying techniques as shown are used in various coating processes in which heated materials are sprayed onto a surface. Raw materials (such as coating precursors) are heated by electrical means (such as plasma or electric arc) and/or chemical means (such as via a combustion flame). Depending on the process and raw materials, coatings with thicknesses ranging from about 20 μm to about 3 mm can be provided using such plasma spraying techniques. Coatings can be applied over large areas at high deposition rates. Using the above techniques, deposition rates are much higher than those achievable by known coating processes such as electroplating or physical and chemical vapor deposition.

In addition to (or in place of) the above exemplary materials, types of coating materials that can be used for plasma spraying include metals, alloys, ceramics, plastics, and composites. The coating materials are fed into the spraying torch in powder form or wire form, and then heated to a molten or semi-molten state and accelerated toward the substrate in the form of micron-sized particles. Combustion or arc discharge can be used as the energy source for plasma spraying. The resulting coating is formed by the accumulation of many layers of sprayed particles. In many applications, the surface of the substrate does not heat up significantly, which is conducive to the coating of many substances (including most flammable substances).

FIG. 9 is a scanning electron microscope image 900 showing the effect of spraying carbon particles (e.g., particle size 20 nm to 40 μm) onto small molten metal particles. Carbon particles sprayed onto small molten metal particles can be used for a variety of special applications. For example, plasma aluminum-graphite composites can be specifically designed to provide coatings for turbo engines. Alternatives include the use of aluminum and titanium alloys. The growth rate of the plasma spray coating material is parabolic. The plasma spray coating material is deposited in a short period of time, and the deposition is largely independent of temperature. Some processes include preheating the material in order to prepare the surface of the material. In some embodiments, sandblasting is also performed with grit to prepare the metal surface. In some embodiments, some portion of the particles sprayed onto the surface are still hot enough to form a covetic bond at the substrate surface. In other cases, the small molten particles are at a temperature to form a metal-metal bond.

The use of the microwave plasma torch technology disclosed herein is capable of producing improved materials compared to the use of conventional torches. Specifically, power control limitations and other configurational constraints inherent in conventional plasma torches limit the ability of conventional plasma torches to independently control input materials and other conditions required to produce carbon that are effective in producing covetic materials that exhibit sufficiently high quality and homogeneity.

FIG. 10 shows a graph depicting a graphene growth temperature curve table 1000 and a binary phase diagram. As an option, the graphene growth temperature curve table 1000 or one or more variations thereof may be implemented in the context of the architecture and functionality of the embodiments described herein. The graphene growth temperature curve table 1000 or any of its aspects may be implemented in any environment. The figure also shows a binary phase diagram, where the x-axis is the carbon concentration in a selected metal (such as copper as shown) expressed as atomic percent. The temperatures in the temperature curve diagram in the figure are also shown in the phase diagram. Various metals (such as silver, tin, etc.) can be used. In some cases, alloys are formed.

The general idea behind the growth of single-layer graphene (SLG) or few-layer graphene (FLG) on molten metal is to dissolve carbon atoms in a transition metal melt at a certain temperature and then allow the dissolved carbon to precipitate out at a lower temperature (i.e., produce a solid from the solution).

Schematic diagram depicting the growth of graphene from molten nickel by, for example, the following steps: (1) melting the nickel while in contact with graphite (as a carbon source); (2) dissolving carbon in the melt at high temperature; and (3) lowering the temperature to grow graphene.

As depicted, keeping the melt in contact with a carbon source at a given temperature will cause the carbon atoms in the melt to dissolve and saturate, based on the metal-carbon binary phase transition. Upon lowering the temperature, the solubility of carbon in the molten metal will decrease, and excess carbon will precipitate on top of the melt.

FIG. 11 is a cross-sectional view of a (known) plasma flame apparatus 1100. This figure is presented to distinguish the use of conventional plasma flame apparatus from the use of the microwave plasma torch disclosed herein. Specifically, although diamond or diamond-like materials can be produced on metal surfaces using conventional plasma flame apparatus, the process requires a significant amount of time for the carbon material to dissolve and diffuse so that the final material is deposited on the metal surface. During the production of the metal-carbon composite material disclosed herein using the presently disclosed embodiments, the desired graphene grows and is locked in the interstices between metal or metal-containing composite layers (or within lattice or matrix sites). However, to do this, the temperature must be adjusted at a high rate. Unfortunately, existing plasma torches do not provide adequate control over temperature and other conditions necessary to reduce the size of interstitial carbon structures to the nanoscale, such as may be desired to achieve the covetic materials sought herein.

In contrast, a pulsed microwave reactor (associated with the presently disclosed embodiments described previously) and corresponding process shown and described in FIG. 12 provide sufficiently detailed control over temperature and other conditions required to reduce the size of interstitial carbon structures to the nanoscale.

FIG. 12 depicts a pulsed microwave process flow 1200 used when “growing” graphene (referring to the systematic deposition or application of graphene layer by layer onto a substantially flat exposed surface of a molten metal particle). Optionally, the pulsed microwave process flow 1200 or one or more variations of any aspect thereof may be implemented in the context of the architecture and functionality of the embodiments described herein. The pulsed microwave process flow 1200 or any aspect thereof may be implemented in any environment.

When using the pulsed microwave process flow 1200 shown, graphene grows onto small molten particles. This is accomplished by interactions that occur within the pulsed microwave reactor around inlet 1204, such as where metal powder and carrier gas are introduced into the reactor chamber. In addition to inlet 1204, process gas ports 1202 and additional ports (such as additional port 1203 ₁ and additional port 1203 ₂ ) are also provided at different heights on one side of the reactor apparatus. The waveguide traverses at least the distance from the location of process gas port 1202 on one side of the reactor to the location of inlet 1204 on one side of the reactor. The details of how to make and use ports to introduce and continuously supply materials into this reactor to grow graphene onto small molten particles are further disclosed below. More specifically, certain components in the reactor of FIG. 12 are shown and described with respect to FIG. 13 .

FIG. 13 is a perspective view of a known pulsed microwave plasma spraying waveguide apparatus 1300 for growing graphene onto small molten particles. As an option, the pulsed microwave plasma spraying waveguide apparatus 1300 or one or more variations thereof may be implemented in the context of the architecture and functionality of the embodiments described herein. The pulsed microwave plasma spraying waveguide apparatus 1300 or any of its aspects may be implemented in any environment.

In this embodiment, a microwave delivery component and a pulsed power source are integrated to form a "surfaguide" (or similar) gas reactor. As shown, the combination of these components is configured to facilitate the growth of graphene onto small molten particles using a microwave plasma torch.

An alternative approach is to perform micro welding using a tungsten inert gas (TIG) plasma source to partially or completely melt the metal. This type of micro welding technique is shown and described with respect to FIG. 14 .

FIG. 14 is a schematic depiction of a micro-welding technique 1400 for growing graphene onto small molten particles. Alternatively, the micro-welding technique 1400 or one or more variations thereof may be implemented within the context of the architecture and functionality of the embodiments described herein. The micro-welding technique 1400 or any aspect thereof may be implemented in any environment.

A low power, low flow TIG welder power source and control unit with a customized plasma containment section can be effectively used to heat all types of metal particles. As shown, the exhaust plume allows the temperature to be maintained high enough to grow graphene when inserted into the surface wave plasma gas decomposition tube. This growth mode involving the control of plasma radicals formed under non-equilibrium conditions composed of hydrocarbons and other added gases provides many tuning opportunities that can be utilized by many different configurations of microwave plasma spraying equipment. Figures 15, 18A1, 18A2, 18B, 18C and 18D and other figures and corresponding written descriptions reveal exemplary configurations of plasma spraying equipment.

FIG. 15 is a schematic depiction of a plasma spraying apparatus in a coaxial configuration 1500. As an option, the coaxial configuration 1500 or one or more variations thereof may be implemented in the context of the architecture and functionality of the embodiments disclosed herein. The coaxial configuration 1500 or any of its aspects may be implemented in any environment.

In a coaxial implementation, microwave energy delivery is achieved via TEM waves fed into an antenna, where the outer portion of the coaxial component is a quartz tube, outside of which are flowing powdered metal particles. In this example, the gas fed into the central region is a hydrocarbon gas such as methane, which absorbs microwave radiation in the central region. The powder is heated by microwave energy escaping from the central region and external induction heating, causing the metal powder (in particulate form) to melt near the inclined portion or tip of the reactor chamber shown. As _CH4 decomposes (to its constituent species, carbon, hydrogen, and/or derivatives thereof), carbon radicals nucleate on the surface of the molten metal droplets via the energy of the plasma radicals. Tuning of microwave duty cycle and tuning of induction heating and tuning of plasma properties help maintain the temperature difference between the melt and plasma decomposition/ionization region. In addition, non-equilibrium temperature allows (promotes) internal lattice placement of graphene/carbon, and rapid quenching creates conditions that are favorable for the growth of other covetic materials.

FIG. 16 is a schematic depiction of a plasma spraying apparatus 1600 showing the evolution of a material being processed by undergoing a series of non-equilibrium energy conditions. As an option, one or more variations of the plasma spraying apparatus 1600 (or any aspect thereof) may be implemented in the context of the architecture and functionality of the embodiments disclosed herein. The plasma spraying apparatus 1600 or any aspect thereof may be implemented in any environment.

The figure depicts the evolution of the material as it passes through the device. Specifically, the figure depicts the regions where different asymptotic changes occur, resulting in graphene growth onto small metal melt particles in the region near the tip. This material is deposited onto a substrate.

FIG. 17 depicts a surface wave plasma system 1700 for growing graphene onto molten particles. As an option, the surface wave plasma system 1700 or one or more variations thereof may be implemented in the context of the architecture and functionality of the embodiments disclosed herein. The plasma system 1700 or any of its aspects may be implemented in any environment.

In the configuration shown, the supply gas is fed into the central region of the apparatus. In this example, a hydrocarbon gas such as methane is used. The hydrocarbon gas absorbs the microwave radiation, which provides the heat source for heating the metal powder. Thus, the metal powder is heated to melt and become molten near the tip using: (1) microwave energy escaping from the central region; and (2) external induction heating. As the hydrocarbon gas decomposes, carbon radicals nucleate on the surface of the molten metal droplet via the energy of the plasma radicals.

Figure 18A1 depicts an axial field configuration 1810 of a plasma spraying torch. The formation of covetic materials has been discussed using several different apparatuses and corresponding processes. Any of the above apparatuses and corresponding processes can be tuned to achieve specific conditions for forming covetic materials. In the specific axial field configuration shown, the process includes generating an electric field 1804 between electrodes to generate a current through a melt of metal and carbon materials. Specifically and as shown, a specially configured plasma torch has an externally controlled field in which the melting particles form a plasma, which in turn becomes a primary electrode. The electrode on the other side of the field is formed by the growth plate 1803 shown. The covetic material is accelerated through the acceleration zone 1821 and then deposited onto the surface. The resulting alloy and covetic material continues to deposit onto the growth plate and/or previously deposited material in the collision zone 1823. This deposition technique produces a material with a homogeneous carbon loading and high concentration.

Input materials may be selected and varied to achieve materials exhibiting specific properties. For example and as shown, the input to the plasma spray torch may include various input gases 1812 and input metal and/or carbon particles 1818. The above inputs may be introduced into one or more input ports 1862. In some cases, the input metal and/or carbon particles are entrained in the stream of input gas 1812. In addition, the growth plate may change its size and composition during ongoing deposition. For example and as shown, the growth plate 1803 may initially be a substrate 1816, on top of which is deposited hot covetic material in a torch stream, which at least partially melts the substrate as the covetic material is deposited. The deposited hot covetic material is cooled from a molten or partially molten state to form a quenched layer.

In this way, any number of layers can be formed. The temperature at the substrate and/or at or near the topmost layer can be controlled so that when the next layer of material is dropped onto the molten metal of the just previously deposited layer, the newly deposited layer grows in a lateral manner to produce a single layer of graphene on the surface of this molten metal. The mechanism differs from other techniques at least in that, compared to the known metal melting method 103 in which carbon is precipitated from a molten metal slurry, the use of the plasma spray torch method 104 disclosed herein results in a quenching in a short period of time, so that there is not enough time for the carbon to precipitate from the matrix. Therefore, the covetic bond remains intact throughout the layer. A moment later, after quenching has formed a metallic solid with well-dispersed carbon, another layer is sprayed on top of it, and so on, thereby forming layers of monolayer graphene that grow, entrap, and rapidly quench to produce a truly covetic material with extremely high carbon loadings within the matrix. As an example, when using the conventional metal melting method 103 (see FIG. 1A ), carbon loadings of 6% carbon metal can be achieved. In contrast, when using the plasma spray torch method 104 (see FIG. 1A ), 60% carbon loadings are easily achieved. In some cases, tight control of the input and process parameters of the plasma spray torch and its environment allows carbon loadings in the resulting material to approach as much as 90%.

Experimental results using plasma spray torches have shown that highly uniform covetic layers can be formed at high loadings by at least two rapid quenching (i.e., "spraying") methods. The first method introduces carbon particles to coat metal particles (e.g., in a plasma), and then sprays the resulting hot mixture onto a much cooler substrate. The second method produces graphene in a plasma, and then introduces molten metal to coat the graphene. In both cases, true covetic (referring to a combination of covalent and metallic chemistry) bonding occurs while in the plasma plume, and rapid quenching of the spray serves to entrap the mixture into an organometallic lattice.

As shown in FIG. 18A2 , the depth or thickness of the quenching layer 1824 can be made thicker or thinner by controlling the distance between the plasma flame 1814 and the substrate and/or by controlling the temperature at the substrate 1816 (e.g., higher or lower than the ambient temperature) and/or by controlling the pressure in and around the reactor.

FIG18B depicts a radial field configuration 1820 of a plasma spraying torch. In this configuration, the molten particles form a plasma inside the torch, where the plasma becomes the primary electrode. The other electrode is formed by one side of the inner wall.

The aforementioned configurations of Figures 18A1, 18A2, and 18B are examples only. Other configurations involving different input materials and different input port configurations are possible without departing from the generality of the plasma spray torch disclosed herein. Furthermore, different configurations involving different input materials and different input port configurations may achieve the same desired results. For example, two different configurations tuned to achieve the same resulting material are shown and described with respect to Figures 18C and 18D. Specifically, the exemplary configurations in Figures 18C and 18D may be used for plasma spray torch deposition of ceramic membrane materials onto carbonaceous particles, such as graphene-containing particles.

In fact, thin film deposition of carbonaceous materials (such as by atmospheric pressure chemical vapor deposition (APECVD) and/or other variations of chemical vapor deposition (CVD)) has entered many areas of material processing. Various composites and coatings involving such carbonaceous materials can exhibit improved physical properties (such as strength, corrosion resistance, etc.). The various 2D carbon and 3D carbon morphological characteristics contribute to the composites and coatings having these improved physical properties by virtue of the molecular level configuration within the carbonaceous materials. In some cases, the use of 2D and 3D carbon in composites and coatings greatly improves the high temperature resistance of the resulting carbonaceous materials; however, in some cases, these high temperatures rise to above ~2100°C, which is high enough to burn the 2D and 3D carbons themselves. Unfortunately, the destruction of the 2D and 3D carbons in turn destroys the benefits of the carbon in the composite or coating in the first place. Therefore, deposition techniques (such as plasma spray torch configurations) are needed to produce composites or coatings that are not affected by temperatures above the carbon combustion temperature.

FIG. 18C depicts this configuration as a non-limiting example only. By tuning the inputs and various in-reactor conditions, the graphene-containing material can be coated with a heat absorbing layer of organically modified silicon (ORMOSIL). Deposition of the ORMOSIL ceramic material onto the graphene-containing material can be achieved by a number of methods, including an atmospheric, reactive plasma enhanced chemical vapor deposition process using a silicon-containing precursor 1841 (such as hexamethyldisiloxane) and a reactive gas such as oxygen. This particular mixture of silicon-containing precursors and oxygen is reactive in the plasma. The molecular dissociation that occurs in the plasma flame causes silicon oxide to be deposited onto surfaces such as the aforementioned growth plate 1803. To this end, the conditions in the reactor are controlled so that the organic modified silicon ceramic is deposited on the surface of the carbonaceous particles as they are formed in the reactor. Controlling the growth in the reactor and the deposition in the reactor (e.g. by controlling the APECVD process) results in the formation of a thin quartz coating around the carbonaceous particles, which in turn are deposited on the substrate. The thin quartz coating acts as a flame retardant to prevent the carbonaceous particles from burning at high temperatures.

FIG. 18D depicts an alternative configuration, by way of non-limiting example only. As shown, a metallic material and/or a carbon-containing material is introduced into the reactor. The microwave energy 1822 is controlled to at least reach a temperature that dissociates the carbon-containing material (such as T(c-dis) in FIG. 10). A silicon-containing precursor 1841 (such as HMDSO, HMDSN, etc.) is introduced into the plasma flame, and the temperature in the plasma afterglow is reduced. As the temperature decreases, carbon particles begin to form, thereby becoming coated with silicon oxide. The carbon particles coated with silicon oxide are then deposited onto the substrate.

In one implementation, a thin layer of these 3D materials, about 10 nm thick, can be deposited onto a substrate that will not burn or catch fire even at 1200°C. This is because the original carbon (such as graphene) is crystalline, so it is not an amorphous material. Rather, the original carbon has been transformed into a state where it can no longer be burned at all.

In one use case, the plasma spray torch technology described above can be used to create new non-eutectic solders. Or, as another use case, the plasma spray torch can spray a coating of material directly onto a substrate to prevent oxidation of the underlying material.

Besides forming a material that will not burn at 1200°C even at atmospheric pressure, placing quartz around materials generally creates huge application advantages.

In addition to organically modified silica, other organic substances can also be used to coat carbon particles or carbon layers. The properties of the coating can be controlled. As an example, the porosity of the surface of the sprayed material can be tuned to be hydraulically smooth.

Plasma spraying torches can be used to form heat absorbing, glass coated, non-flammable graphene composed of graphene and silicon, wherein silicon coats the graphene so that the graphene can withstand temperatures above 1600°C. This heat absorbing, glass coated, non-flammable graphene absorbs infrared energy.

A specific method for producing an organically modified silicon coating includes the following steps (for example): (1) introducing a silicon-containing precursor into a plasma spray torch apparatus; (2) combining the silicon-containing precursor with a carrier gas having carbon particles entrained in the precursor gas; and (3) coating the carbon particles with silicon.

The properties of the flame retardant and infrared shielding materials produced by the plasma spray torch configurations of FIG. 18C and/or FIG. 18D can be tuned at least in part by controlling the time-temperature path in the reactor. More generally, the properties of the materials produced by the plasma spray torch configurations of FIG. 18A1, FIG. 18A2, FIG. 18B, FIG. 18C, or FIG. 18D can be tuned at least in part by controlling (e.g., pulsing) the microwave energy within the reactor.

FIG. 19 is a graph 1900 depicting energy versus time during pulse on and pulse off periods. More specifically, the graph shows a complete time cycle, from time T=0 to 50 microseconds, where the microwaves are continuously turned on, and then the remainder of the cycle depicts the time that the microwaves are turned off. The plotted curves depict (1) the change in density and (2) the change in temperature during the cycle. At time T=0, the temperature is at its lowest point (as depicted at the origin of the graph). The temperature rises rapidly and then drops, during which time the plasma density reaches a relatively stable value. When the microwaves are turned off at time T=50 microseconds, both the plasma density and the temporary electron temperature drop rapidly. The pulse time and duty cycle can be controlled to achieve a specific density and temperature at any point in time.

FIG. 20A1 depicts an image showing the organometallic bonding that occurs when carbon and copper are combined using a plasma spray torch. As shown, carbon 2052 is deeply embedded in copper 2054. As generally understood and referred to herein, organometallic chemistry refers to the study of organometallic compounds, compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali metals, alkaline earth metals, and transition metals, and sometimes expanded to include metalloids such as boron, silicon, and tin. In addition to bonding to organic radical fragments or molecules, bonding to "inorganic" carbon, such as carbon monoxide (carbonyl), cyanide, or carbide, is also generally considered to be organometallic. Discussion of organometallic compounds may include related compounds such as transition metal hydrides and metal phosphine complexes, but strictly speaking, they are not necessarily organometallic.

In organometallic chemistry, organocuprants contain carbon and copper chemical bonds and can have unique physical properties, syntheses, and reactions. The structure and reactivity of organocuprants can be quite varied, but there are some restrictions on the oxidation state of copper(I), such as Cu ⁺ . As a ^d10 metal center, it is related to Ni(0), but due to its higher oxidation state, it participates in less π-back bonding. Organic derivatives of Cu(II) and Cu(III) can be called intermediates, but are rarely isolated or even observed. In terms of geometry, copper(I) adopts a symmetric structure, consistent with its spherical electron shell. Generally, one of three coordination geometries can be adopted: linear 2-coordinate, trigonal 3-coordinate, and tetrahedral 4-coordinate. Organocopper compounds form complexes with various soft ligands such as alkyl phosphines (R ₃ P), sulfides (R ₂ S), and cyanides (CN ^- ).

By any one or more of the above techniques, the carbon depicted in FIG. 20A1 and FIG. 20A2 can be chemically bonded to the copper, rather than merely juxtaposed to the copper to adhere to it via van der Waals forces (i.e., distance-dependent interactions between atoms or molecules). Unlike ionic or covalent bonds, van der Waals forces are not generated by chemical electronic bonds; van der Waals forces are relatively weak and therefore more susceptible to perturbations. Furthermore, van der Waals forces vanish rapidly at longer distances between interacting molecules. Instead, organometallic bonding between the metal and the carbon is desired.

Figure 20A2 depicts an image representing a graded composition of substances applied to a substrate material and showing three material property regions. Bulk metal region 2066 is the first of the three material property regions. As shown, the first material property region includes metal in a first crystalline form having significant metal bonds between metal atoms present in the first material property region. This first material property region is substantially adjacent to a second material property region that at least partially overlaps the first material property region. Covetic material region 2064 includes at least some carbon atoms in a second crystalline form, wherein the second crystalline form has at least some non-polar covalent bonds between some of the carbon atoms present in the second material property region and metal atoms present in the first material property region. The top surface region 2062 is a third material property region that at least partially overlaps with the second material property region. This top surface region includes additional carbon atoms oriented in a third crystal form. The third crystal form is characterized by having at least some non-polar covalent bonds between individual carbon atoms in the additional carbon atoms present in the third material property region. In various embodiments, there may be some metal atoms in any of the regions and some carbon atoms in any of the regions. However, this embodiment is characterized by a higher metal content region 2074 adjacent to the bulk metal region 2066. In various embodiments, there may be some carbon atoms in any of the regions and some metal atoms in any of the regions. However, this embodiment is characterized by a higher carbon content region 2072 adjacent to the top surface region 2062.

Figure 20B is a material evolution table 20B00 depicting several layered configurations that occur when carbon is added to bulk aluminum. In these embodiments, the material is sprayed onto an existing carbon-rich covetic substrate or carbide layer to produce carbon-carbon bonds through carbon sintering and/or metal melt encapsulation, followed by adhesion to form a composite film. Material evolution table 20B00 is just one example of a composite material (silicon carbide) sprayed onto an aluminum bulk material. The process can be tuned to produce covetic or covetic-like films deposited onto bulk materials. The resulting material can then be coated to produce a functionalized top layer. One possible configuration of an apparatus for spraying a composite material onto a substrate is shown in FIG. 21A .

FIG. 21A depicts an apparatus for spraying a molten mixture of materials onto a substrate. The figure depicts a microwave reactor that includes multiple zones within a storage vessel. Pulsed microwave energy is delivered to the storage vessel. A hydrocarbon process gas 605 is provided through an inlet port. The microwave energy heats the process gas to a temperature high enough to form a plasma. The expansion of the material within the storage vessel produces a plasma plume. The continuous addition of material to the storage vessel combined with the above expansion produces a torch effect in and around the plume. Due to the high temperatures in and around the plasma plume, carbon and hydrogen dissociate to form several different hydrocarbons (e.g., CH ₃ , CH ₂ ). As the temperature continues to increase (as shown in the first zone 2104), all or nearly all of the carbon atoms dissociate from the hydrogen. The hydrogen-only material is separated from the solid carbon material using any known technique, such as using a gas-solid separator.

At the interface between the first region 2104 of the storage vessel and the second region 2106 of the storage vessel, molten metal or molten metal composite or molten ceramic-metal or metal matrix or any kind of metal mixture is introduced into the storage vessel (as shown) through a second inlet. The location of the second inlet is selected based on the size of the plasma plume and/or the temperature of the molten metal at the entry point into the storage vessel. More specifically, the metal melt 2108 is introduced into the reactor at a location where the molten metal mixes with the carbon material. As the mixture flows through the storage vessel (e.g., at a high rate), the mixture cools to a lower temperature. The flowing mixture leaves the storage vessel at a high rate, causing the mixture of carbon and molten metal to spray out from outlet 2110. The mixture is deposited (e.g., by spraying the spray material 2112) onto the target substrate 2116. Various mechanisms for controlling the uniformity of the spray material 2112 and/or the resulting deposited material 2114 are shown and discussed with respect to FIGS. 23A-23D.

The temperature in the second zone is low enough that at least some of the carbon precipitates out of the mixture. However, most of the dissociated carbon remains mixed with the molten metal. When the molten metal mixed with the carbon reaches the target substrate 2116, it cools to a solid. During the transition from the molten mixture to the solid deposit, the carbon is trapped between the metal layer and the carbon layer. At certain temperatures, the carbon forms nonpolar covalent bonds with the metal, thereby producing a covetic material. Due to the increase in cohesive forces (such as nonpolar covalent bonds) between the metal matrix and the carbon, the covetic material exhibits a range of mechanical, thermal, electrical, and tribological properties.

Such covetic materials are the result of using pulsed microwave energy to control the energy distribution of material components in the first and second regions of the reactor. More specifically, the energy distribution of material components in the first and second regions of the reactor can be controlled in part by pulsed microwaves and in part by pre-melting metal particles in the external environment of the reactor chamber (e.g., so that fully molten or partially molten metal is introduced into the reactor chamber). Any known technique can be used alone or in combination to melt the metal particles. In this way, the degree and/or mixing of fully molten or partially molten particles can be controlled.

FIG. 21B depicts a method for spraying a covetic material onto a substrate. The method may be used in conjunction with the apparatus of FIG. 21A. As shown, the method is performed using a microwave reactor having an inlet for a process gas, an inlet for a metal melt, and an outlet. Prior to operation, the microwave reactor is configured to have an inlet for a hydrocarbon process gas, an inlet for a metal melt, and an outlet (operation 21B02). At operation 21B10, the inlet is used to introduce the hydrocarbon process gas into a first region of the reactor. Using microwave energy, the temperature in the first region of the reactor is increased, causing the hydrocarbon process gas to dissociate into carbon and hydrogen species before contacting the metal melt. A different inlet is used to introduce the metal melt into a second region of the reactor (operation 21B20). The elevated temperature in the second zone is maintained until the dissociated carbon is mixed with the metal melt (operation 21B30). The action of the plume described above serves to move the mixture into the third zone of the reactor (operation 21B40). Moving away from the microwave energy source has the effect of lowering the temperature of the mixture until at least some of the carbon condenses out of the mixture (operation 21B50). However, even with the lowered temperature, the plasma torch effect serves to move the mixture through the outlet at a high rate (operation 21B60). In this manner, the molten mixture is sprayed onto the substrate (operation 21B70).

FIG. 21C is a schematic diagram depicting a plasma spraying process for spraying a film. As shown, carbon radicals, polycyclic aromatics, graphene sheets, and metal particles are mixed at high temperatures in a plasma reactor (such as the first region 2104 shown by the finger). Nucleation occurs at these high temperatures, and growth and assembly begin as the temperature decreases within the reactor (such as the second region 2106 shown by the finger). One possible growth mechanism is depicted by submicron-sized aluminum particles coated with a few layers of graphene. These submicron-sized aluminum particles can be held together using a combination of metallic bonds, nonpolar covalent bonds, and covetic bonds. More specifically and as shown at the 2 nm level, carbon atoms are bonded to aluminum atoms. The carbon atoms are organized in coherent graphene planes located within an aluminum matrix, preferably interlaced between the basal planes of the aluminum matrix. The previous discussion involving aluminum is merely an example. Other metals can be used. In fact, coherent graphene planes can be located not only in a face-centered cubic (FCC) metal lattice (again, preferably between the basal planes), but also in a body-centered cubic (BCC) metal lattice, or in a hexagonal close-packed (HCC) metal lattice.

The coated particles may then be sintered to form particles of approximately 100 μm in diameter. These semi-molten particles are then accelerated through the reactor and collide with the substrate (such as in the first pass) or with a previously deposited layer of collision particles (such as in the second or Nth pass).

FIG. 22A depicts an apparatus for encapsulating carbon particles with molten metal. The configuration of the apparatus in FIG. 22A differs from the configuration of the apparatus in FIG. 21A at least in that a melting apparatus 2209 is used to control the introduction of the molten metal. When the molten metal is introduced into the reactor, the metal melt is controlled to produce molten metal encapsulating the carbon particles.

FIG. 22B depicts a method for coating carbon particles with molten metal. Prior to operation, a microwave reactor is configured to have an inlet for a carbonizing process gas, an inlet for a metal melt, and an outlet (operation 22B02). In operation 22B10, the inlet is used to introduce the carbonizing process gas into a first region of the reactor. The method differs from the method of FIG. 21B in at least that, in operation 22B30, the temperature in different regions of the reactor is maintained so that some of the carbon particle material is formed from dissociated carbon. The action of the aforementioned plume is used to move the mixture into a third region of the reactor (operation 22B40). In operation 22B50, at least some of the carbon particles are coated with molten metal. Some bonds are formed between the constituent atoms of the carbon particles and the atoms of the metal melt. In operation 21B60, the metal-encapsulated carbon particles move through an outlet, thereby further reducing the temperature. When the metal-encapsulated particles are deposited onto a substrate (operation 21B70), additional bonds are formed between the metal-encapsulated carbon and the metal of the substrate.

Figures 23A, 23B, 23C, and 23D depict exemplary deposition techniques according to some implementations.

As shown in Figure 23A, the deposited material has a curved shape characterized by a middle region of higher elevation and end regions of lower elevation. In some cases, this is the desired shape for a small amount of deposited material. In other cases, it is desirable to spray the deposited material over a larger area. This can be accomplished by moving the substrate relative to the spray or by moving the spray relative to the substrate. Figure 23B depicts a flexible substrate 2310 disposed on a supply reel. The flexible substrate can be pulled onto and around a take-up reel. In this manner and in the configuration of Figure 23B, the spray deposits the covetic material uniformly onto the moving substrate. When the relative movement between the sprayed material 2112 and the substrate is controlled, the resulting deposited material has a uniform thickness.

In some cases, it is desirable to have an uneven but uniform patterning at the surface of the deposited material. In such cases, the movement of the substrate may be stepped through a series of discrete locations to form the patterning of FIG. 23C. Additionally or alternatively, a slotted antenna may be disposed between the sprayed material 2112 and the substrate. The slotted antenna functions by distributing the spray uniformly over the lateral distance of the slotted antenna. Using this slotted antenna, a single point of the sprayed material 2112 may have a thickness and surface uniformity substantially as shown in FIG. 23D.

Figures 24A and 24B depict known techniques for depositing materials onto a substrate. As shown in Figure 24A, the carbon agglomerates are held together by the use of a binder, such as a polymer. This results in a weak bond at the interface between the carbon agglomerates and the substrate. Figure 24B depicts the coating of the carbon material onto the substrate using a binder. Known depositions using binders suffer from the adverse effects of peeling. Furthermore, even when the surface of the substrate is mechanically pretreated and/or pretreated by deposition of a binder material, the interaction between the substrate and the carbon agglomerates is weak.

As previously mentioned, coatings based on depositing materials onto substrates using adhesives and/or using coating techniques (such as shown and described with respect to FIGS. 24A and 24B ) suffer from peeling, low strength characteristics, and other undesirable mechanical properties. An improvement based on plasma spraying techniques is shown and discussed in FIGS. 25A and 25B .

25A and 25B depict exemplary deposition techniques for producing nonpolar covalent bonds at the surface of a substrate according to some embodiments. Specifically and as shown, when the techniques disclosed herein are used, a covetic material is formed by nonpolar covalent bonds between carbon and the substrate. As such, no binder is required or used. Furthermore, many of the nonpolar bonds formed at the interface between the substrate and the covetic material are strong covalent bonds. In one particular case, when the substrate is aluminum, nonpolar covalent bonds are formed between atoms in the face-centered cubic structure of the aluminum and carbon atoms in the hexagonal structure. A schematic diagram of the interfacial bonding is depicted in FIG. 25B .

Figures 26A, 26B, 26C, and 26D present schematic diagrams depicting how nonpolar covalent bonds are formed between sites in the square shape of the face-centered cubic structure of aluminum and sites in the hexagonal shape that occur in certain crystal structures of carbon.

FIG. 26A is an orthogonal view showing a square shape of the face-centered cubic structure of aluminum. FIG. 26B is an orthogonal view showing a hexagonal shape that occurs in certain crystal structures of aluminum.

FIG. 26C depicts one possible superposition of hexagonal shapes that occur in certain crystal structures of carbon on top of the square shape of the face-centered cubic structure of aluminum. FIG. 26D depicts the non-polar covalent bonds that form at certain sites. The example of the face-centered cubic structure of aluminum is just one example. Other metals with other crystal structures are possible. The unexpected properties exhibited by some embodiments are hypothesized to be caused by the non-polar covalent bonding between carbon atoms and metal atoms being sufficient/effective to be able to "trap" all or substantially all (e.g., at least 90%, at least 95%, at least 98%, at least 99%, etc.) of the "free" electrons that are normally present in compounds that exhibit metallic bonding, thereby altering the properties normally associated with the presence of "free" electrons in metals and metal-containing compounds. For example, certain embodiments may be characterized in that the surface of the inventive composition of matter has substantially no "free" electrons, and therefore exhibits reduced thermal and/or electrical conductivity. In addition, for embodiments having substantially no "free" electrons, the surface of the inventive composition does not oxidize when exposed to ambient air.

FIG. 26E is an example of a layered covetic material 26E00 in which a graphene-like structure is sandwiched between layers of metal material. The lower layer of metal material is a substrate layer. The top layer of metal material is formed from a quenched material that was previously melted while in a reactor. The graphene-like structure sandwiched between the layers of metal material is trapped between the two metal layers due to the metal-metal bonds formed between the two metal layers. In addition to the metal bonds, other bonds are formed that serve to enclose the graphene-like material between the metal layers. In some locations, there are defects in the carbon lattice. Various types of bonds are formed between or near such defects.

Any or all of the aforementioned techniques for forming covetic materials can be used in many applications involving many different types of substrates. In addition, the relative movement between the spray and the substrate can be controlled to produce a deposit of any thickness. The relative movement can be controlled using any known technique. For example, the outlet can be moved over a fixed substrate. This can be accomplished using a handheld device or a robotically controlled device that moves relative to the fixed substrate. In some cases, the substrate can be subjected to a bias so that at least some of the material ejected from the outlet is electrostatically attracted to the surface of the substrate. This has applicability in applications where the substrate is not uniformly flat. As examples, applications where the substrate is not uniformly flat may include: (1) molded components used in machinery that are subject to corrosive conditions; (2) turbine blades; (3) heat exchanger components, etc., many of which are discussed further below.

In other cases, the properties of the deposit (e.g., thickness, lateral uniformity, etc.) may be enhanced by using various chemical vapor deposition techniques and/or combinations of various chemical vapor deposition techniques. As just one example, the states or parameters associated with plasma enhanced chemical vapor deposition techniques known in the art may be controlled to optimize the properties of the deposited covetic material layer. As another example, rather than depositing the covetic material onto a surface to form a film or coating, the covetic material may be formed into particles (e.g., by spraying into a relatively low temperature environment) and the particles collected in powder form. Various techniques involving the production and use of powdered covetic materials are briefly discussed below.

Powdered covetic material

In some cases, rather than forming the covetic material as a film or coating on or in a substrate, the covetic material may be delivered in the form of a covetic material powder. This powdered covetic material may be collected as it leaves the reactor, cooled to a temperature below the melting point of the covetic material and collected in powder form. The powder may then be processed at room temperature (e.g., storage and transport, pouring, mixing, etc.). The powder may then be remelted and pressed into a molded part or remelted and re-sprayed. As an example, components for use in highly corrosive environments may be formed from such powdered covetic materials using injection molding or extrusion. A number of equipment may be used, alone or in combination, to form and transport covetic material powders. An exemplary apparatus is shown and discussed with respect to FIGS. 27A, 27B1, and 27B2.

FIG. 27A depicts an exemplary apparatus 27A00 for cooling a sprayed material 2112 using a cooling zone 2702 to produce a powdered covetic material 2710 while forcing the spray through an outlet 2110 of a microwave reactor. Any one or more cooling techniques in any combination may be used to reduce the temperature of the covetic material in the cooling zone 2702 to a temperature below the melting point of the covetic material. The cooling zone 2702 may house one or more devices to cause cooling. For example and as shown, the collection container 2704 may be equipped with one or more devices to cause a cyclonic effect in the collection container, thereby increasing the time for reducing the temperature of the covetic material. In some cases, controlling the time for cooling the covetic material (e.g., by increasing or decreasing the time) allows the covetic material to anneal with highly regular bonding. In some cases, controlling the time for cooling the covetic material allows the covetic material to crystallize into a highly regular crystalline structure while still remaining in powder form. In some embodiments, a mechanical drum-stirrer may be installed between the outlet 2110 of the microwave reactor and the collection container 2704. The drum-stirrer may be cleaned or replaced periodically.

Alternatively or additionally, and where it is convenient and/or desirable to contain and/or transport the powdered covetic material in a fluid, a fluidized bed apparatus may be used. For example, to avoid the formation of aggregates and/or agglomerates of powder particles, the powdered covetic material may be maintained (e.g., suspended) in a liquid. In some embodiments, a fluidized bed apparatus may be mounted between the outlet 2110 of the microwave reactor and the collection container 2704. One embodiment of such a fluidized bed apparatus is shown and described with respect to FIGS. 27B1 and 27B2.

Figures 27B1 and 27B2 depict an exemplary fluidized bed apparatus 27B00 for cooling and processing powdered covetic materials in a fluid.

As shown, the molten metal and carbon mixture is forced through the outlet of the reactor and into the top of the fluidized bed 2750. As the molten metal and carbon mixture is forced to leave the outlet, it cools in a manner that forms particles. The particles are acted upon by the downward force of gravity (in a downward direction as shown), while the process fluid 2754 is driven from the bottom of the fluidized bed to generate an upward force. In this way, the particles are accelerated toward the bottom of the fluidized bed at a rate of acceleration that is slower than the rate of acceleration of the local gravity. The flow dynamics can be partially adjusted by the geometry of the fluidized bed. For example and as shown, a fluidized bed of a certain length can form a conical body 2762, wherein the first end of the conical body has a first dimension D1, and wherein the second end of the conical body has a second dimension D2, and wherein D1>D2. The temperature within various portions of the fluidized bed may be controlled in part by a power source 2752 (as shown) that powers the coils and/or by a heat source 2760 that heats the process fluid 2754 before it enters the bottom of the fluidized bed.

Pressure and flow rates in and at the boundaries of the fluidized bed, along with other conditions, are used to cause the powder and fluid mixture to behave together as a fluid. The mixture exhibits many of the properties and characteristics of a fluid, such as the ability to flow freely under gravity and/or the ability to be pumped using fluid handling techniques.

In the embodiment of Figures 27B1 and 27B2, the fluidized bed has multiple ports located at different heights of the conical body. This allows the first powder 2756 ₁ in the fluid to flow out at a specific temperature/pressure, and the second powder 2756 ₂ in the fluid to flow out at a second different specific temperature/pressure. The flow through the multiple ports can be controlled so that the collection container can receive any ratio or amount of the first powder 2756 ₁ in the fluid and the second powder 2756 ₂ in the fluid.

Method for forming covetic material

Table 3 shows some non-limiting examples of methods for forming powdered covetic materials.

Illustrative method 1

In some embodiments of method 1, structured carbon (such as a carbon allotrope) is formed in a first zone of a microwave reactor (such as by dissociation of a carbonizing process gas). In a second zone at a lower temperature than the first zone, the structured carbon is decorated with a metal to form a metallized carbon material (such as an organometallic material). The metallized carbon material is further cooled to a temperature below the melting point of the metal. In some embodiments, the metallized carbon material is initially in the form of carbon particles decorated with a metal. The particles are further cooled to form a powder. The powder can be collected and transported to an application facility. The powder comprising the metallized carbon material having a covetic bond can be remelted and used with any known technique for forming components from powders. As just examples, components may be formed from powders using compression molding followed by remelting, isostatic pressing followed by remelting, hot forging, metal injection molding, laser sintering, etc.

Illustrative method 2

In this method 2, one or more hydrocarbon gases (or in some cases gases and liquids) are introduced into the system. By way of example only, the gases and/or liquids that may be introduced into the system include methane, ethane, methylacetylene-propylene propane (MAPP), and hexane. In a first zone 2104 at a first temperature, carbon atoms dissociate from other atoms (e.g., from hydrogen). Molten metal 2108 is introduced into the reactor as metal particles. Then, in a second zone 2106, the carbon produced in the first zone is combined with the metal particles. The carbon may grow on the surface of the metal particles and/or grow inside the metal particles. In some cases and under some conditions, carbon growth includes growth of 2D carbon on or in metal particles. In other cases and/or under other conditions, carbon growth includes growth of 3D carbon on or in metal particles. In any of the foregoing growth cases, the growth can occur to the maximum extent permitted by the crystal lattice. For example, the molten metal can be aluminum having a face-centered cubic (FCC) crystal structure, and the carbon can form a solid solution of aluminum up to a particular concentration. In some embodiments, the carbon forms a solution of the metal up to a concentration determined by the properties of the metal (such as the crystal structure), and then precipitates from the metal-carbon solution to form 2D or 3D carbon on and/or in the metal particles.

The growth in this method 2 is carried out under non-equilibrium thermal conditions. Specifically, various different thermal conditions are used to control (for example) the following: (1) a first temperature (such as a higher temperature) in the first zone required to control the aforementioned dissociation, and (2) a second temperature (such as a lower temperature) in the second zone for controlling the initial melting of the metal powder and/or the formation and properties of the metal-carbon particles in the second zone. The temperatures in these two zones can be independently controlled. Using this method, the sprayed material is a true covetic material that exhibits true covetic properties.

Illustrative method 3

In other non-limiting examples, the material and/or coating on the input particles can be produced or deposited from mixed materials such as trimethylamine (TMA), trimethylglycine (TMG), and methylacetylene-propylene glycol. The particles can be cooled and collected in powder form. Some examples of particles that can be produced from the target material in the first region are phase-controlled carbon, silicon carbide, metal oxides, metal nitrides, or metals. In some cases, the input particles are metals and a compound film (such as a metal oxide or metal nitride) is coated on the metal input particles, while in other cases, the input particles contain a compound material and a metal coating is deposited on the input particles. Some examples of particles that may be produced from the input gas in the first zone are carbon allotropes (such as natural carbon), silicon, ZnO, AlOx, and NiO.

In some embodiments, a gas comprising various non-hydrocarbon gases or alcohols is input into a first region, and the first region includes a sputtering device and a power source, wherein the sputtering device is configured to generate a plurality of ionic species from a selected target material. The target material and the ionic species are combined to form a plurality of particles. The power source can be an AC, DC, RF, or high power pulsed magnetron sputtering (HIPIMS) power source and can be configured to generate a plurality of ionic species from a target material by tuning the power, voltage, frequency, repetition rate, and/or other characteristics of the power source.

FIG. 27C is a schematic diagram illustrating a plasma spraying process for producing a powdered covetic material.

Powder material processing sequence

FIG. 27C shows a visual representation of an exemplary powdered material processing sequence from calcination and particle nucleation (as shown in the first region 2104) to graphene growth (as shown in the second region 2106), cooling of the semi-molten particles (as shown in the cooling region), and collection of the powdered covetic material (as shown in the collection region and into the collection container 2704). The mechanism behind the efficacy of the exemplary powdered material processing sequence is now briefly discussed.

In the absence of metal precursors (either metallo-organic or particulate form), microwave plasma dissociates methane to form carbon radicals (and polycyclic aromatics/acetylene), which then form few-layer (FL) graphene (or stacked sheet) structures, respectively. However, in the presence of metal precursors in the plasma region (such as the reactors of Figures 21A and 22A), the metal (from metallo-organic cores or particles) can be used as seed sites for heterogeneous carbon growth (such as carbon in the form of ionized radicals, graphene cores, or polycyclic aromatics (acetylene)).

When using metals with low solubility such as Al or Cu, graphene sheets can be grown onto the metal surface (e.g., via adsorbed atoms/monomers or as clusters). The characteristics of the growth depend at least in part on the symmetry and minimization of the interfacial free energy at the metal surface. Thus, carbon growth occurs at the metal particles while metal atom respray events occur at the surface to produce mixed and/or layered metal/carbon structures. As is known in the art, the radius of the metal particle (e.g., surface curvature) may affect the solubility of carbon in the metal particle. As an example, a smaller radius (e.g., corresponding to a higher curvature) increases the solubility above equilibrium (at a flat surface), which in turn may affect the thickness of the graphene layer.

Once the powdered covetic material 2710 has been collected in the collection container, the powdered covetic material can be further processed using known techniques (e.g., injection molding techniques, other techniques using powdered metals).

Manufacturing technology using powdered covetic material

FIG. 28 depicts a method for manufacturing a component from a powdered covetic material using injection molding techniques. As shown, the method begins after a set of properties are collected for a component to be used in a particular application and/or environment (operation 2810), and then a particular powdered covetic material is selected based on at least one of the properties for the application or environment (operation 2820). The selection can be based on desired mechanical properties of the component, and/or based on desired corrosion resistance properties of the component in an environment corresponding to its intended use, and/or other desired properties. The selection can be based on multiple desired properties, and in some cases, the selection tool solves an optimization problem based on a set of properties and an objective function.

Once the covetic material is selected (operation 2820), the selected powdered covetic material (operation 2825) is melted (operation 2830) and introduced into the mold (operation 2840). A specified temperature and a specified pressure are maintained in the mold for a specified duration (operation 2850), after which the temperature and pressure in the mold are brought to about 30°C and about atmospheric pressure (operation 2860). The assembly is released from the mold (operation 2870) and deployed in the intended application (operation 2880).

As mentioned previously, the selection of a particular covetic material can be based on a variety of desired properties, some of which can be used as variables in the objective function. In some cases, the selection of a particular covetic material can be based on a particular primary property (e.g., mechanical strength, weight, corrosion resistance, etc.). In some cases, the property of interest is a ratio of other properties, such as strength:weight, specific heat:weight, etc. In some cases, the primary property will be maximized (or minimized) under constraints on one or more of the other properties.

As such, powdered covetic materials can be deployed in a wide range of applications. In many cases, the resulting components made from powdered covetic materials outperform components made from other materials. Some exemplary applications associated with certain key properties are shown and discussed with respect to FIG. 29 below.

FIG. 29 is a table 2900 depicting various properties of covetic materials. The properties shown include mechanical properties, thermal conductivity, oxidation resistance, durability, resistance to high temperature softening, fatigue resistance, and electrical conductivity. Individual parameters and/or combinations of these parameters become dominant in selecting a particular covetic material for a particular application.

As just one example, when selecting a covetic material to be used in the manufacture of a corrosion resistant valve, oxidation resistance may be the primary parameter. As another example, when selecting a particular covetic material to be used in the manufacture of a blade for an aircraft engine turbine, mechanical properties such as strength to weight ratio that are subject to minimal constraints on strength may be the primary mechanical properties. The blade may also need to exhibit very high fatigue resistance.

Typically, covetic materials not only exhibit the above properties, but also have a lower density than the metal or alloy used in making the covetic powder. The lower density often corresponds to a lower weight of the resulting component compared to the same component made from the metal or alloy in the absence of the carbon loading. Thus, truck components (such as the cockpit component shown), automotive components (such as door fenders, roof panels, etc.), motorcycle components, bicycle components, and various components of air vehicles (such as structural components) and/or watercraft and/or space-based vehicles or platforms can utilize covetic materials with a lower weight to strength ratio than the base metal or alloy used to make the covetic material.

As another example, covetic materials often exhibit excellent thermal conductivity, allowing structural components formed from covetic materials to be used in high temperature applications (such as heat sinks for electronic devices, industrial heat exchangers, etc.).

As yet another example, covetic materials often exhibit excellent corrosion resistance. More specifically, covetic laminates made using the aforementioned techniques exhibit extremely high corrosion resistance, even at the topmost layers, such as at the interface between the component and the environment. This property is particularly significant when components made from covetic materials are subjected to harsh environments.

As another example, covetic materials can be tuned for surface smoothness. More specifically, covetic laminates made using the aforementioned techniques exhibit extremely high surface smoothness. This surface smoothness property is particularly significant when the covetic material is used as a thermal shield, such as may be required in applications where friction at the surface (such as friction generated when a fluid flows over the surface at high speeds) generates harmful heat at the surface. By using the techniques disclosed herein, specific compositions of covetic materials and/or by using specific techniques disclosed herein for deposition of covetic materials, a hydrodynamically smooth surface can be produced, which can in turn be used in air vehicles and/or space-based vehicles.

In some embodiments, one set of properties may dominate other properties. For example, the surface of a space-based vehicle (such as a satellite) may need to be substantially non-reflective to a certain range of electromagnetic radiation (such as substantially non-reflective to visible light), while at the same time, the surface of the space-based vehicle may need to be thermally insulating (such as non-conductive). The tuning techniques above are applicable to such situations, where a particular desired property (such as non-reflectivity) dominates the tuning of the plasma spray torch in order to produce a substantially non-reflective surface, even at the expense of other properties.

The properties shown and described with respect to FIG. 29 are examples only. Additional properties and/or combinations of properties may be necessary or desired in various applications, and such additional properties may be manifested in the resulting material based on the tuning of the inputs and control of the plasma spray torch. As examples only of the aforementioned additional properties, such properties and/or combinations of properties may include or be related to the following: strength-to-weight measurements, and/or specific density, and/or mechanical toughness, and/or shear strength, and/or flexural strength, etc.

Some applications (e.g., for high stress/high temperature operation, or for operation in chemically harsh environments) have specific specifications for corrosion resistance, and/or strength, and/or hardness, and/or other properties of the final material or component. In some cases, these specific specifications can be met by using an alloy that is then used to form the component corresponding to the specific application. VIM furnaces are often used to form the alloys. Sometimes, carbonaceous materials in powder form are added to the alloy mixture in order to reduce weight while maintaining the strength and/or other properties of the alloy.

Unfortunately, a VIM furnace generates a strong magnetic field. The effect of this strong magnetic field on the composition of the powder is generally stronger than the effect of gravity on the composition of the powder. Therefore, this magnetic field has a detrimental effect, namely, causing the powder to eject from the VIM furnace even before the powder has a chance to enter the crucible of the VIM furnace, have a chance to melt, and subsequently disperse in the mixture melt. One technique for addressing this detrimental ejection of powder from a VIM furnace is to pelletize the powder into a dense form so that when the form is introduced into the VIM furnace, it is not ejected due to the magnetic forces of the VIM furnace. Instead, the pelletized form enters the crucible of the VIM furnace, causing it to melt inside the VIM furnace, and causing it not to mix into the molten mixture.

Thus, a carbon-containing alloy is formed, preferably one having at least some (more preferably all) of the physical properties described above with respect to the covetic material. Such physical properties should be understood to include, but are not limited to, high carbon loading (e.g., greater than 1.5%, greater than 5%, greater than 15%, greater than 40%, greater than 60%, and up to 90% carbon in the material, according to various embodiments); carbon is substantially uniformly dispersed in the surface layer and/or bulk of the material; carbon is present at interstitial sites in the crystal lattice of the metal alloyed with the carbon; carbon aggregates and/or agglomerates are absent at the grain boundaries of the material; Figures 30A1 and 30A2 depict problems and solutions associated with melting metal decorative carbon in powder form compared to melting metal decorative carbon in pellet form. The figures are presented side by side to specifically illustrate the problems (30A100) and solutions (30A200) associated with using powders in a VIM processor.

As is known in the art, vacuum induction melting relies on a high power current generating source 3006 to melt metal within a vacuum environment 3002. The induction heating process generates eddies within a conductor (e.g., metal). The eddies, in turn, generate heat. The magnetic field generated by the heated coil generates an upward force. Each individual particle of powder 3004 is not heavy enough to overcome the upward force generated by the electromagnetic field, resulting in unwanted ejection 3003 of the metal decorative carbon powder. FIG. 30A2 depicts the solution disclosed herein to this unwanted ejection, namely, by compressing many individual particles of powder into pellets 3008. Thus, the gravitational force acting on the pellets overcomes the force of the magnetic field on the powder components. This solves the aforementioned problem that the magnetic field of the VIM processor has a stronger effect on the powder than gravity. Therefore, the pellets enter the crucible and are heated together with the components of the mixture.

Once the mixture reaches its melting point, a magnetic field begins to stir the metal alloy. The alloy melt - which includes the carbon-containing components dispersed in the alloy's molten matrix - can now be poured into a mold specific to the component being used for a given application.

FIG. 31 depicts a method of using pellets 3108 to minimize or eliminate material ejection during introduction of pellets 3108 into a VIM processor 3110. The figure is presented to illustrate an exemplary material processing process for pelletizing powdered material 3004 prior to use in a VIM processor. In additional methods, the VIM processor 3110 may be used in place of or in conjunction with a vacuum arc melting apparatus, an electron beam furnace, an ion plating furnace, a plasma flame source, a smelting furnace, a conventional metal-metal melting furnace, or any equivalents and/or components thereof as would be understood by one of ordinary skill in the art after reading this disclosure.

To obtain a powdered material, a supply gas (e.g., a hydrocarbon such as methane) is flowed into a plasma reactor to obtain a plasma containing dissociated carbon atoms and dissociated hydrogen atoms. A metal melt (e.g., a nickel melt) is injected into the plasma at a specific location in the plasma plume, such as where hydrogen and carbon atoms are completely dissociated. The injected metal melt combines with the dissociated carbon atoms to form metal-decorated carbon molecules, some of which merge with other metal-decorated carbon molecules. When cooled to a temperature below the melting point of the injected metal, the precipitate leaves the plasma reactor as a powdered material 3104.

After the metal-decorated carbon powder is collected from the plasma reactor (step 3114), the metal-decorated carbon molecules may be separated from the dissociated hydrogen molecules (e.g., H2) in a gas-solid separator or other collection container located at the outlet of the plasma reactor. For example and as shown, as will be understood by those skilled in the art after reading this disclosure, the gas-solid separator container 3102 may be implemented using equipment such as gravity separators, cyclone separators, scrubbers, electrostatic separators, filters, etc.

In the example shown, metal-decorated carbon (solid) and hydrogen molecules (gas) may be placed in a cyclonic gas-solid separator vessel 3102. This particular configuration uses the concept of inertia to separate solids (e.g., metal-decorated carbon) from gases (e.g., hydrogen). Due to the molecular weight difference between the metal-decorated carbon and the hydrogen, the lighter material (in this case, the hydrogen) will be more affected by the vortex generated within the cyclonic gas-solid separator vessel. As a result, the hydrogen will be forced (by cyclonic action) to travel upward, thus separating the gas from the heavier powdered material 3104 (e.g., metal-decorated carbon molecules). The shape of the gas-solid separator vessel helps the metal-decorated carbon particles flow downward toward the bottom of the vessel. The downward flow is in the opposite direction to the upward flow of hydrogen. Thus, the metal-decorated carbon particles can be collected for further processing.

Once the metal-decorated carbon powder has been isolated from the hydrogen and captured, the metal-decorated carbon is compressed to form rigid body pellets 3108 (step 3116). The pelletization can be accomplished, for example, by using a pelletizer 3106, such as a 12-ton press that is automatically actuated or manually operated. Although this example shows the use of a 12-ton press as the pelletizer 3106, any pelletizing technique and/or equipment that a person skilled in the art will understand as suitable for producing pellets of sufficient quality to avoid ejection from the VIM processor may be used without departing from the scope of the present invention.

The pelletization of metal decorated carbon exploits the mechanics of how the metal pelletized carbon and the magnetic flux of the VIM interact under gravity. More specifically, gravity has a stronger effect on the pellets than the magnetic flux. Therefore, when pellets (rather than powder) are introduced into the VIM processor 3110, the previously mentioned issues regarding ejection of material due to magnetic forces are eliminated.

Once the pellets are introduced into the crucible of the VIM processor, the pellets will begin to melt and mix with the other contents of the crucible (step 3118). During this step, as the pellets melt, they are evenly dispersed within the metal mixture. To promote even dispersion, the VIM crucible can be loaded with pellets alone, with the pellets placed on top of the metal powder, or with the metal powder placed below and above the pellets, according to various embodiments.

The resulting melt 3112 may then be poured into a mold (step 3120) and/or used in conjunction with injection molding equipment to form a component (e.g., a turbine blade, an automotive component, a medical device, etc.). In some cases, the resulting output of the VIM processor (e.g., melt 3112) is cooled and then powdered using any suitable equipment for use with other mechanical part forming methods (e.g., 3D printing) and then used in any application (step 3122).

FIG. 32 depicts a melt 3112 placed into a mold 3202. The melt 3112 may be placed into a mold 3202 of any shape or form. Once the melt cools, the component may be removed from the mold and used in its intended application.

As just one example, a mold for a turbine blade may be used. A melt consisting of a metal mixture and a carbon-containing component may then be placed into the turbine blade mold and cooled. Once cooled and removed from the mold, the turbine blade may be used in its intended application. As another example, the melt may be cooled, then powdered, and then packaged for use in a 3D printer or other additive manufacturing technology/equipment.

FIG. 33 depicts a simplified schematic diagram of pellet processing according to various methods. As described in detail above with reference to FIG. 31 , a powdered material 3104 is obtained, for example, as output from a microwave plasma reactor, separated from unwanted gases, and pressed into pellets using a pelletizer 3106. Preferably, the pelletizer 3106 includes a mold whose physical configuration/arrangement is suitable for producing pellets having a desired geometric shape. As shown in FIG. 33 , the mold 3106a is configured to produce generally cylindrical pellets (or "pucks") having a diameter of about 1 cm. Of course, those skilled in the art will appreciate that the geometric properties of the pellets may be selected and/or adjusted based on the properties of the VIM processor (or equivalent) that will be used to produce the desired material (e.g., magnetic field strength, volume, etc.). It is noteworthy that the pellets produced according to the experiments presented in FIG. 33 were produced without the need for a chemical binder.

As also shown in FIG. 33 , and experimentally demonstrated, the present invention successfully produces pellets consisting essentially only of natural graphene (3108a), as well as pellets formed of metal-decorated carbon (e.g., decorated graphene) (3108b). Either type of pellet can be produced using substantially the same technique, with the only difference being the composition of the powder used to produce the pellets.

In another experiment schematically presented in FIG. 34 , pellets (such as pellet 3108) were dispersed in an isopropyl alcohol solution by manual stirring. After stirring, which may be performed manually, using an ultrasonic wand (or other mechanism for ultrasonic stirring), etc., the resulting suspension exhibits permeability as will be appreciated by one of ordinary skill in the art after reading this disclosure. Magnetic Test 2 verified the dispersion of the nickel-decorated carbon.

Invent ideas

Various embodiments, aspects, features, advantages, implementations, configurations, arrangements, etc. of the invention concepts have been described above with reference to the figures. It should be understood that, unless otherwise expressly stated herein, such embodiments, aspects, features, etc. may be combined or modified in any suitable manner that a person skilled in the art would understand after reading the disclosure without departing from the scope of the disclosure. It is clear that the following invention concepts exist in the preferred characteristics, configurations, etc. of the invention concepts presented herein, and may be used in any suitable manner, combination, or arrangement while still within the disclosed scope of the invention.

According to one aspect, a composition of matter comprises one or more particles, and at least some of the particles independently comprise a metal lattice having one or more coherent planar graphene layers disposed in the metal lattice. At least some of the carbon atoms of the one or more coherent planar graphene layers may be disposed in interstitial sites of the metal lattice. For example, the one or more coherent planar graphene layers may be partially or completely interstitially interlaced between basal planes of the metal lattice. Preferably, the metal lattice comprises about 15 wt % to about 90 wt % carbon, and about 15 % to about 60 wt % of the carbon in the particles is present at interstitial sites thereof. Additionally, in some methods, the metal lattice is characterized by a crystal structure selected from face-centered cubic (FCC), body-centered cubic (BCC), and hexagonal close-packed (HCC). In some methods, the one or more coherent planar graphene layers consist of a single layer of graphene. Alternatively, the one or more coherent planar graphene layers include at least five graphene layers and no more than fifteen graphene layers. Depending on the selected embodiment, the one or more coherent planar graphene layers are each independently substantially defect-free. The metal lattice may include one or more metals selected from the group consisting of aluminum, copper, iron, nickel, titanium, tungsten, chromium, molybdenum, cobalt, manganese, niobium, and combinations thereof. For example, the metal lattice may be or include an Inconel nickel alloy, and the Inconel nickel alloy may be a superalloy formed from one or more metals selected from the group consisting of nickel, chromium, aluminum, copper, iron, titanium, tantalum, molybdenum, cobalt, manganese, and niobium. In addition, the Inconel nickel alloy may be selected from the group consisting of Inconel 600, Inconel 617, Inconel 625, Inconel 690, Inconel 718, and Inconel X-750. At least some of the carbon atoms of the one or more graphene layers are preferably covalently bonded to metal atoms of the metal lattice. More preferably, the covalent bonds between the carbon atoms of the graphene and the metal atoms include non-polar covalent bonds. Likewise, at least some of the carbon atoms of the one or more graphene layers may be covalently bonded to other carbon atoms of the one or more graphene layers, and some or all of the covalent bonds between the carbon atoms of the graphene may include non-polar covalent bonds. Continuing with reference to the bonding within the material composition, the one or more particles may be completely or substantially free of polar covalent bonds. In addition, the metal lattice of each of the one or more particles is substantially or completely free of ionic bonds. "Substantially" is understood to mean a composition in which any polar bonds, ionic bonds, or other mentioned types of bonds present in the composition have no effect or a negligible effect on the structural, physical and functional properties of the material composition. The particles may be characterized by lack of carbon aggregates and/or agglomerates at their grain boundaries, having a diameter in the range of about 20 nm to about 3.5 μm, being pressed into pellets, or any combination of these characteristics. According to certain aspects, the maximum discernible feature size of the composition of matter is in the range of about 0.1 nm to about 1 μm. The particles may be pressed into pellets.

In the foregoing specification, the disclosure has been described with reference to specific implementations of the disclosure. However, it is apparent that various modifications and changes may be made thereto without departing from the broader spirit and scope of the disclosure. For example, the process flow described above is described with reference to a particular ordering of process actions. However, the ordering of many of the process actions described may be changed without affecting the scope or operation of the disclosure. This specification and accompanying drawings are to be considered in an illustrative, rather than a restrictive, sense.

Claims (15)

A composition of matter comprises one or more particles, wherein at least some of the one or more particles independently comprise a metal lattice having one or more coherent planar graphene layers disposed in the metal lattice. A composition of matter as in claim 1, wherein at least some of the carbon atoms of the one or more coherent planar graphene layers are disposed in interstitial sites within the metal lattice. A composition of matter as in claim 1, wherein the one or more coherent planar graphene layers are interstitially interlaced between basal planes of the metal lattice. The composition of matter of claim 1, wherein the metal lattice comprises one or more metals selected from the group consisting of aluminum, copper, iron, nickel, titanium, tungsten, chromium, molybdenum, cobalt, manganese, niobium, and combinations thereof. A composition of matter as in claim 1, wherein at least some of the carbon atoms of the one or more graphene layers are covalently bonded to metal atoms of the metal lattice; and wherein the covalent bonds between the carbon atoms of the graphene and the metal atoms comprise non-polar covalent bonds. The composition of matter of claim 1, wherein at least some of the carbon atoms of the one or more graphene layers are covalently bonded to other carbon atoms of the one or more graphene layers; and wherein the covalent bonds between the carbon atoms of the graphene include non-polar covalent bonds. The composition of matter of claim 1, wherein the one or more particles do not substantially comprise polar covalent bonds. The composition of matter of claim 1, wherein the metal lattices of the one or more particles do not substantially include ionic bonds. The composition of matter of claim 1, wherein the one or more particles independently comprise from about 15 wt % carbon to about 90 wt % carbon. The composition of matter of claim 1, wherein the metal lattices of the one or more particles comprise from about 15 wt % to about 60 wt % carbon at interstitial sites thereof. A material composition as claimed in claim 2, wherein the carbon atoms are substantially uniformly dispersed in the metal lattice. A composition of matter as claimed in claim 1, wherein the grain boundaries of the metal lattice are substantially free of carbon aggregates and/or agglomerates. A composition of matter as in claim 1, wherein each particle is characterized by a lack of carbon aggregates and/or agglomerates at its grain boundaries. A composition of matter includes: an inconel nickel alloy having graphene disposed in a metal lattice of the inconel nickel alloy. A composition of matter comprises a metal lattice having at least about 15 wt % carbon disposed therein, wherein the metal lattice comprises a metal selected from the group consisting of iron, tungsten, chromium, molybdenum, cobalt, manganese, niobia, and combinations thereof.