DE102005003579B4 - Pyrotechnic set, process for its preparation and its use - Google Patents

Abstract

Pyrotechnic set, with
at least one nanostructured, porous fuel body; and
an oxidizing agent provided in the cavities of the at least one fuel body,
wherein the oxidizing agent is a fluorine-releasing substance
characterized,
a protective layer is provided on the surface of the cavities of the at least one fuel body,
wherein the surface of the cavities of the at least one fuel body is functionalized with a monolayer of perfluorinated alkyl or aryl radicals and fluorine.

Description

The The present invention relates to a pyrotechnic composition according to the The preamble of claim 1 and a method for the production a pyrotechnic phrase according to the preamble of the claim 8th.

Such a pyrotechnic compound or reactive substance and such a production process are described, for example, in US Pat DE 102 04 895 A1 described. The known reactive substance consists of fuel bodies in whose cavities in the size range of 1-1,000 nm an oxidizing agent is introduced and whose surfaces are provided with a protective layer which can be broken to induce the reaction between the fuel and the oxidizing agent. A fuel body according to this DE 102 04 895 A1 is defined in the context of the present invention as a nanostructured, porous fuel body.

The high rate of reaction of this known reactive substance is caused by the very short distances or diffusion paths between the oxidant (electron acceptor) and the fuel (electron donor, reducing agent), which are of the order of less than 50 nm. With the diffusion coefficients of 10 ^-10 -10 ^-14 cm ² s ^{-1 present here} , such a great reduction of the diffusion ^path causes a considerable acceleration of the diffusion process as an important variable influencing the reaction rate.

In the case of DE 102 04 895 A1 silicon, boron, aluminum, titanium or zirconium is selected as the fuel, while oxygen-releasing oxidants based on ammonium, alkali and alkaline earth nitrates, perchlorates and peroxides are used. In the reaction between the fuel and the oxidant, for example, the high-boiling metal oxides indicated in the following table are formed as reaction products. Table 1 fuel boron aluminum silicon titanium zircon metal B ₂ O ₃ Al ₂ O ₃ SiO ₂ TiO ₂ ZrO ₂ Phase at RT firmly firmly firmly firmly firmly boiling point 2250 ° C 3300 ° C 2,477 ° C ~ 2,500 ° C 4300 ° C

Out For this reason, the pressure-volume work of the reaction products as basis for the use of the reactive substance for example in actuators very much highly limited. Also can the oxidic combustion products do not react further exothermically. For example, it is used in the case of oxygen-sublimated explosives the afterburning of the resulting substances C and CO with the atmospheric oxygen, to increase the steam energy; however, in the case of the oxide-based burn-off products, this is the case here described conventional Reactive substances not possible.

outgoing from the above-described prior art is the present Invention, the object of a pyrotechnic composition with a nanostructured, porous fuel bodies so on, that in the reaction between fuel and oxidant gaseous Reaction products arise, which themselves perform pressure-volume work.

These Task is solved by a pyrotechnic composition having the features of the claim 1 or a method for producing a pyrotechnic composition with the features of claim 8. Advantageous embodiments and further developments of the invention are the subject of the respective Dependent claims.

Of the pyrotechnic composition of the invention comprises at least one nanostructured, porous Fuel body, a protective layer on the surface of the at least one fuel body and an oxidizing agent provided in the cavities of the at least one fuel body is on. As the oxidizing agent according to the present invention used a fluorine-releasing substance.

mit m = maximale Wertigkeit des Brennstoffs M
welche im Gegensatz zu den oben genannten hochsiedenden Metalloxiden als gasförmige Metallfluoride selbst Druck-Volumenarbeit leisten. Die folgende Tabelle 2 zeigt beispielhaft die Siedepunkte einiger Metallfluoride, die als Reaktionsprodukte bei dem pyrotechnischen Satz der Erfindung entstehen können. Tabelle 2 Brennstoff Bor Aluminium Silizium Titan Zirkon Metalloxid BF₃ AlF₃ SiF₄ TiF₄ ZrF₄ Phase bei RT gasförmig fest gasförmig fest fest Siedepunkt –99°C 1.272°C –90°C ~ 284°C subl. 600°C subl. The nanostructured, porous fuel body corresponds to that in the DE 102 04 895 A1 defined fuel body. On the disclosure of the DE 102 04 895 A1 For this reason, full reference is made in this respect. The advantage of reacting the fuel with a fluorine-releasing substance as the oxidizing agent is the formation of volatile fluids according to the equation

with m = maximum valency of the fuel M
which, in contrast to the abovementioned high-boiling metal oxides as gaseous metal fluorides themselves perform pressure-volume work. The following Table 2 shows, by way of example, the boiling points of some metal fluorides which may be formed as reaction products in the pyrotechnic composition of the invention. Table 2 fuel boron aluminum silicon titanium zircon metal BF ₃ Alf ₃ SiF ₄ TiF ₄ ZrF ₄ Phase at RT gaseous firmly gaseous firmly firmly boiling point -99 ° C 1272 ° C -90 ° C ~ 284 ° C subl. 600 ° C subl.

One Comparison of the boiling points given in Table 2 for the Reaction products resulting metal fluorides with the above in Table 1 specified boiling points of the high-boiling metal oxides as reaction products of the conventional Reactive material clearly shows the advantage of using a fluorine releasing substance as the oxidizing agent of the pyrotechnic composition of the present invention.

The Oxidizing agent is preferably selected from the group consisting from fluorocarbons, fluorine nitrogen compounds and compounds made of fluorine, carbon and nitrogen. In the case of fluorocarbons as Oxidizing agent becomes nanodisperse carbon partly in the form of fullerenes and nanotubes released; This nanocarbon reacts under thermal excitation in excellent manner with the atmospheric oxygen strongly exothermic and increased so that the steam energy in an advantageous manner. In the case of fluorine nitrogen compounds elevated also the liberated nitrogen the pressure-volume work of the corresponding Systems.

To illustrate the pressure-volume work performed by the reaction products of the pyrotechnic set of the present invention, the following table shows exemplary gas volumes V (in ml / mol) at 298 K for the following various fuel / oxidant systems (2) through (6). shown. 4n B + 3 (-C ₂ F ₄ -) _n → 4n BF _{3 (g)} + 6n C _(s) (2) Al 4n + 3 (C ₂ F ₄ -) _n → 4n AlF _{3 (g)} + 6n C _(s) (3) n Si + (-C ₂ F ₄ -) _n → n SiF _{4 (g)} + 2n C _(s) (4) n Ti + (-C ₂ F ₄ -) _n → n TiF _{4 (g)} + 2n C _(s) (5) n Zr + (-C ₂ F ₄ -) _n → n ZrF _{4 (g)} + 2n C _(s) (6) Table 3 system B / PTFE Al / PTFE Si / PTFE Ti / PTFE Zr / PTFE V [ml / mol] 89655 89655 22414 22414 22414

Particularly suitable fluorine-releasing oxidants are those substances which can be introduced by means of a thermally induced diffusion process due to low melting or boiling points in the cavities of the nanostructured, porous fuel body. Likewise, the fluorine-releasing substances may be soluble in fluid media capable of penetrating the voids of the nanostructured porous fuel bodies. In particular, supercritical carbon dioxide CO _{2 (Scr)} is therefore used as a preferred solvent because it evaporates residue-free on the one hand and on the other hand reduces the risk of fire and explosion in the manufacturing process.

Suitable, by thermally induced diffusion processes in the cavities of the nanostrukturier th, porous fuel body storable fluorocarbons are for example the following compounds, which are classified for the purpose of unique identification with the Chemical Abstracts Service (CAS) number assigned in square brackets: octafluoronaphthalene (C ₁₀ F ₈₎ [313-72-4] , Decafluorobiphenyl (C ₁₂ F ₁₀ ) [434-90-2], octakis (trifluoromethyl) cubane C ₈ (CF ₃ ) ₈ [50782-50-8], polyfluoro [60] fullerene C ₆₀ F ₄₈ [160359-80- 8], perfluorotridecane C ₁₃ F ₂₈ [376-03-4], perfluorotetradecane C ₁₄ F ₃₀ [307-62-0], perfluoropentadecane C ₁₅ F ₃₂ [2264-03-1], perfluorohexadecane C ₁₆ F ₃₄ [355- 49-7], perfluoreicosane C ₂₀ F ₄₂ [37589-57-4] and perfluorotetracosane C ₂₄ F ₅₀ [1766-41-2]. Fluorocarbons which can be incorporated, in particular by solvent-induced diffusion, are hexafluoropropene-vinylidene fluoride copolymer (Viton ^™ ) [9011-17-0], polychlorotrifluoroethylene [9002-83-9] (Kel-F ^™ waxes and oils) and polyvinylidene fluoride (PVDF) [24937- 79-9].

Suitable fluorine nitrogen compounds are, for example, complex compounds of perfluoro-azonium cations and their homologs, as well as transition metal fluoridate anions such as [NF ₄ ] ₂ [NiF ₆ ]. The latter compounds are stable at room temperature, manageable and allow very high fluorine storage densities. A suitable compound of fluoro, carbon and nitrogen is, for example, poly (bis (difluoroamino)) ethylene (-C ₂ H ₂ (NF ₂ ) ₂ -) _n .

Of the at least one fuel body the pyrotechnic composition of the invention is preferably made of silicon, Boron, aluminum, titanium, zirconium or a mixture thereof formed.

The inventive method for the preparation of a pyrotechnic composition comprises the steps of Providing at least one nanostructured, porous fuel body, the Provision of the surface of the at least one fuel body with a protective layer and the provision of the cavities of at least a fuel body with an oxidizing agent. Furthermore the process is characterized in that the oxidizing agent is a fluorine-releasing substance.

The Advantages of using a fluorine-releasing substance as an oxidizing agent for one nanostructured, porous fuel bodies and preferred oxidizing agents of this type have already been explained in detail above, which is why on a repeated list these points should be omitted at this point.

As already mentioned, the oxidizing agent can be introduced, for example, by thermally induced diffusion into the cavities of the at least one fuel body. Alternatively, it is also possible that the oxidizing agent is introduced by solvent-induced diffusion in the cavities of the at least one fuel body, wherein as a solvent supercritical carbon dioxide CO _{2 is} preferably used.

ablaufen. Es wurde nun gefunden, dass diese Grignard-Reaktion auch beim Einsatz der erfindungsgemäßen Brennstoffe abläuft. Durch die kontrollierte thermische Vorbehandlung wird der Brennstoff (B, Al, Si, Ti, Zr) mit einer Monolage aus perfluorierten Alkyl- bzw. Arylresten und Fluor gemäß dem folgenden Schema funktionalisiert. Auf diese Weise kann je nach Dauer und Temperatur der thermischen Vorbehandlung die thermische Empfindlichkeit der Reaktivstoffe verringert, aber zugleich deren Umsetzungsgeschwindigkeit erhöht werden.Another feature of the invention is the thermal pretreatment of the nanostructured porous fuel bodies for the purpose of controlling sensitivity and rate of conversion. It is known that fluorocarbon compounds such as poly (tetrafluoroethylene) with metals such as magnesium in the condensed phase in a Grignard-like reaction with insertion of the metal into the CF bond according to the following equation

expire. It has now been found that this Grignard reaction also proceeds when using the fuels according to the invention. The controlled thermal pretreatment functionalizes the fuel (B, Al, Si, Ti, Zr) with a monolayer of perfluorinated alkyl or aryl radicals and fluorine according to the following scheme. In this way, depending on the duration and temperature of the thermal pretreatment, the thermal sensitivity of the reactive substances can be reduced, but at the same time their rate of reaction can be increased.

So becomes the fuel body made of aluminum, for example, with polytetrafluoroethylene heated to a maximum of 550 ° C, causing an insertion of the aluminum into the C-F bond comes. The reactive substance thus produced can then be targeted, for example be detonated by electrothermal action.

Of the described above and in the attached claims defined pyrotechnic kit according to the present invention can be used particularly advantageously as a pulse element, in which little space is available, such as for projectiles, for the attitude control of satellites, for the control of missiles, missiles, projectiles and the like, for ignition of explosives or to ignite of propellants, pyrotechnic charges and the like.

Claims (19)

Pyrotechnic set, comprising at least one nanostructured, porous fuel body; and an oxidizing agent provided in the cavities of the at least one fuel body, wherein the oxidizing agent is a fluorine-releasing substance, characterized in that a protective layer is provided on the surface of the cavities of the at least one fuel body, the surface of the cavities of the at least one fuel body is functionalized with a monolayer of perfluorinated alkyl or aryl radicals and fluorine. Pyrotechnic kit according to claim 1, characterized in that that the oxidizing agent is selected from the group consisting of fluorocarbons, fluorine nitrogen compounds and compounds of fluorine, carbon and nitrogen. Pyrotechnic composition according to claim 2, characterized in that the oxidizing agent is selected from the group consisting of octafluoronaphthalene (C ₁₀ F ₈ ), decafluorobiphenyl (C ₁₂ F ₁₀ ), octakis (trifluoromethyl) cubane C ₈ (CF ₃ ) ₈ , polyfluoro [ 60] fullerene C ₆₀ F ₄₈ , perfluorotridecane C ₁₃ F ₂₈ , perfluorotetradecane C ₁₄ F ₃₀ , perfluoropentadecane C ₁₅ F ₃₂ , perfluorohexadecane C ₁₆ F ₃₄ , perfluoric acid C ₂₀ F ₄₂ and perfluorotetracosane C ₂₄ F ₅₀ . Pyrotechnic kit according to claim 2, characterized in that that the oxidizing agent is selected from the group consisting of hexafluoropropene-vinylidene fluoride copolymer, Polychlorotrifluoroethylene and polyvinylidene fluoride. Pyrotechnic composition according to claim 2, characterized in that the oxidizing agent Po ly (bis (difluoroamino)) ethylene (-C ₂ H ₂ (NF ₂ ) ₂ -) _n . Pyrotechnic kit according to claim 2, characterized in that that the oxidizing agent is selected from the group of complex compounds of perfluoro-azonium cations and its homologs, as well as transition metal fluoridate anions. Pyrotechnic kit according to one of claims 1 to 6, characterized in that the at least one fuel body Silicon, boron, aluminum, titanium, zirconium or a mixture thereof is formed. Process for the preparation of a pyrotechnic composition with the steps: Providing at least one nanostructured, porous Fuel body; and Provide the cavities of the at least one fuel body with an oxidizing agent, wherein the oxidizing agent is a Fluorine-releasing substance is characterized, that the surface the cavities of the at least one fuel body provided with a protective layer, the surface of the cavities of the at least one fuel body to provide the surface with a protective layer with a monolayer of perfluorinated alkyl or aryl radicals and fluorine is functionalized. Method according to claim 8, characterized in that that the oxidizing agent is selected is selected from the group consisting of fluorocarbons, fluorine nitrogen compounds and compounds of fluorine, carbon and nitrogen. A method according to claim 9, characterized in that the oxidizing agent is selected from the group consisting of octafluoronaphthalene (C ₁₀ F ₈ ), decafluorobiphenyl (C ₁₂ F ₁₀ ), octakis (trifluoromethyl) cubane C ₈ (CF ₃ ) ₈ , polyfluoro [60 ] fullerene C ₆₀ F ₄₈ , perfluorotridecane C ₁₃ F ₂₈ , perfluorotetradecane C ₁₄ F ₃₀ , perfluoropentadecane C ₁₅ F ₃₂ , perfluorohexadecane C ₁₆ F ₃₄ , perfluoric acid C ₂₀ F ₄₂ and perfluorotetracosane C ₂₄ F ₅₀ . Method according to claim 9, characterized that the oxidizing agent is selected is selected from the group consisting of hexafluoropropene vinylidene fluoride copolymer, Polychlorotrifluoroethylene and polyvinylidene fluoride. A method according to claim 9, characterized in that the oxidizing agent is poly ₍₂ H (NF _{2) 2} -C ₂ -) (bis (difluoroamino)) ethylene _n. Method according to claim 9, characterized in that that the oxidizing agent is selected is from the group of complex compounds of perfluoro-azonium cations and its homologs, as well as transition metal fluoridate anions. Method according to one of claims 8 to 13, characterized that the at least one fuel body of silicon, boron, aluminum, Titanium, zirconium or a mixture thereof is formed. Method according to one of claims 8 to 14, characterized that the oxidizing agent by thermally induced diffusion in the cavities of the at least one fuel body is introduced. Method according to one of claims 8 to 14, characterized that the oxidizing agent by solvent-induced diffusion in the cavities of the at least one fuel body is introduced. A method according to claim 16, characterized in that the solvent is supercritical carbon dioxide CO ₂ . Method according to one of claims 8 to 17, characterized that the surface the cavities of the at least one fuel body to provide the surface with a protective layer of a thermal pretreatment under inert gas is subjected to a first exotherm of the binary system. Use of the pyrotechnic composition according to one of claims 1 to 7 or one with the Ver Drive according to one of claims 8 to 18 prepared pyrotechnic composition as a pulse element for projectiles, for attitude control of satellites, for the control of missiles, missiles, projectiles and the like, for the ignition of explosives or for the ignition of propellants, pyrotechnic charges and the like.