Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
  • B22F5/009—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of turbine components other than turbine blades
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/22—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip
  • B22F3/225—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip by injection molding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
  • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
  • B22F7/062—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools involving the connection or repairing of preformed parts
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
  • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
  • C04B35/638—Removal thereof
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B37/00—Joining burned ceramic articles with other burned ceramic articles or other articles by heating
  • C04B37/02—Joining burned ceramic articles with other burned ceramic articles or other articles by heating with metallic articles
  • C04B37/021—Joining burned ceramic articles with other burned ceramic articles or other articles by heating with metallic articles in a direct manner, e.g. direct copper bonding [DCB]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
  • B22F2998/10—Processes characterised by the sequence of their steps
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B1/00—Producing shaped prefabricated articles from the material
  • B28B1/002—Producing shaped prefabricated articles from the material assembled from preformed elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
  • B28B1/00—Producing shaped prefabricated articles from the material
  • B28B1/24—Producing shaped prefabricated articles from the material by injection moulding
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
  • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
  • C04B2235/602—Making the green bodies or pre-forms by moulding
  • C04B2235/6027—Slip casting
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
  • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
  • C04B2237/32—Ceramic
  • C04B2237/34—Oxidic
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
  • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
  • C04B2237/32—Ceramic
  • C04B2237/34—Oxidic
  • C04B2237/341—Silica or silicates
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
  • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
  • C04B2237/32—Ceramic
  • C04B2237/36—Non-oxidic
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
  • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
  • C04B2237/32—Ceramic
  • C04B2237/36—Non-oxidic
  • C04B2237/361—Boron nitride
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
  • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
  • C04B2237/32—Ceramic
  • C04B2237/36—Non-oxidic
  • C04B2237/363—Carbon
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2237/00—Aspects relating to ceramic laminates or to joining of ceramic articles with other articles by heating
  • C04B2237/30—Composition of layers of ceramic laminates or of ceramic or metallic articles to be joined by heating, e.g. Si substrates
  • C04B2237/40—Metallic
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
  • F23R2900/00—Special features of, or arrangements for continuous combustion chambers; Combustion processes therefor
  • F23R2900/00018—Manufacturing combustion chamber liners or subparts

Definitions

• the present invention relates to a method for producing a sealing segment for use in compressor and turbine components, by powder injection molding, as well as to a sealing segment for use in compressor and turbine components composed of at least one first molded article as a base element and of at least one second molded article exhibiting a higher abrasive wear rate than the first molded article, as a rub strip.
• Sealing segments of this kind are used, in particular, when working with what are generally known as gap-maintaining systems in the compressor and turbine components. Sealing segments, respectively sealing systems of this kind have the function of maintaining a minimal sealing gap between rotating blading and a housing, as well as between stationary blading and the rotating rotor hubs, and of thereby ensuring stable operating characteristics in the context of a highest possible efficiency.
• the rotating components of the turbine typically have sealing fins which run in against honeycomb seals in a manner known per se.
• a honeycomb seal of this kind is described by World Patent Application WO 2004/061340 A1. This known honeycomb seal is made of an individual molded article fabricated by powder-metallurgical injection molding.
• the known running-in process can easily lead to overheating of the sealing fins when the contact with the honeycomb material lasts too long or the resistance generated by the rubbing away of the honeycomb structures becomes too great. Therefore, damage to the sealing fins cannot be ruled out in the case of the known sealing segments, respectively corresponding abradable coatings.
• an object of the present invention to devise a method for producing a sealing segment and a sealing segment produced accordingly for use in compressor and turbine components, which, on the one hand, make it possible to inexpensively manufacture a broad array of sealing segment geometries and, on the other hand, to reduce the load that the compressor and turbine components are subject to when running in against the sealing segments.
• a method according to the present invention for producing a sealing segment for use in compressor and turbine components by powder injection molding includes the following method steps in accordance with the present invention: a) preparing a first homogeneous mixture of a metal powder or a mixture of metal powders or a ceramic powder or a mixture of ceramic powders and at least one binding agent; b) producing a first molded article by injection molding the first mixture; c) preparing a second homogeneous mixture of a metal powder or a mixture of metal powders or a ceramic powder or a mixture of ceramic powders and at least one binding agent, the second mixture being selected to have a higher abrasive wear rate than the first mixture following a subsequent joint sintering process; d) producing a second molded article as a rub strip by injection molding the second mixture; and e) joining the first and second molded articles to produce the sealing segment.
• a cost-effective and also individual production of the requisite sealing segments is ensured by using the powder injection molding method.
• all injection-moldable and sinterable metals, metal alloys, as well as ceramics may be used for the powder injection molding of the first and second molded articles. Mixtures of the metal powder or ceramic powder are also conceivable.
• the sinterable ceramics may include nitride ceramics, oxide ceramics and silicate ceramics, as well as carbides, for example.
• the present invention makes it possible to satisfy a broad array of material requirements for a sealing segment of this kind in compressor and turbine components.
• this concerns the simple production of complicated geometries using the powder injection molding method, and, on the other hand, the targeted adaptation of the material selection for producing the first and second molded articles, which may be carried out in conformance with the actual technical conditions.
• the properties of the second molded article that pertain to the abrasion characteristics, such as the generation of only low frictional energies and resistances, the effective chip formation and removability of the abraded material, or also that relate to preventing an ignition of the abraded material during grazing contact, in a targeted manner, to the turbine components making grazing contact, such as sealing fins, for example.
• the honeycomb structure may be entirely eliminated and, accordingly, planar layers may be produced economically.
• the present invention makes it possible for the first formed element, which is used as a base element or fastening element of the sealing segment, to be adjusted to the relevant technical and material engineering conditions. This relates, in particular, to temperature resistance and erosion resistance.
• the first and second molded articles may be joined immediately following the production thereof and prior to releasing of the same in a joint process.
• first and second molded articles may be joined following a separate release process and prior to a subsequent joint sintering process that the molded articles undergo.
• first and second molded articles may be joined following a separate release and sintering process that they undergo. In the latter case, mechanical, as well as chemical joining processes are possible.
• the higher abrasive wear rate of the second molded article is achieved by reducing the metal powder or ceramic powder content in the second mixture.
• the metal powder or ceramic powder content is only approximately 15-30% by volume.
• the sintering process yields a porous structure due to a reduction in intergranular contact.
• no separation effects ensue in the second mixture, and a homogeneous porosity distribution is obtained. There is also no need for any change in the process parameters.
• the higher abrasive wear rate of the second molded article is achieved by using metal powders and ceramic powders having reduced sintering activity.
• metal powders having a lower degree of purity i.e., higher C- and O-concentration may be used, for example.
• air-atomized instead of inert gas-atomized metal powder, leads to a higher C- and O-coverage of the surfaces and thus to a reduced sintering activity.
• the advantage of a very porous structure is derived due to a reduction in the intergranular contact, respectively in the sintering neck formation.
• inexpensive metal powders or ceramic powders may be used. A homogeneous porosity distribution, as well as a reduction in separation effects are achieved. There is again no need for any changes in the process parameters.
• the higher abrasive wear rate of the second molded article is achieved by admixing binder polymers, which do not entirely decompose during release and/or sintering processes, into the second mixture.
• the binder polymers may be selected from the group including the phenolic resins or novolak.
• Admixing binder polymers advantageously reduces the sintering activity. Carbon residues are produced in the grain interstices of the metal or ceramic powder particles in the sintered product, making it possible to achieve good abrasive wear properties.
• no separation effects occur in the context of a homogeneous porosity distribution.
• the higher abrasive wear rate of the second molded article is achieved by admixing fillers into the second mixture.
• the fillers may be formed from easily cleavable inert materials, such as graphite, bentonite or hexagonal boron nitride and/or from materials which at least partially decompose during the release and/or sintering and contribute to pore formation in the second molded article. Evaporation advantageously takes place during sintering, for example, thereby resulting in a pore formation in the scraping layer, respectively in the second molded article.
• the fillers do not decompose, and that they remain in the sintered product, i.e., in the scraping layer, respectively in the second molded article, in the grain interstices of the metal or ceramic powder particles. Overall, therefore, the result is a quite readily cleavable, respectively abradable rub strip.
• the pore formation is optionally effected by surface oxidation in the later use of the sealing segment, for example when graphite is selected as a filler.
• a multiplicity of homogeneous mixtures of metal powder or a mixture of metal powders or a ceramic powder or a mixture of ceramic powders and at least one binding agent are prepared in accordance with method steps a) through d) to produce a corresponding multiplicity of molded articles and a sealing segment resulting therefrom.
• a sealing segment according to the present invention for use in compressor and turbine components composed of at least one first molded article as a base element and/or fastening element and at least one second molded article having a higher abrasive wear rate than the first molded article, as a rub strip, the first and the second molded articles each being produced by powder injection molding.
• the at least two-layered design of the sealing segment according to the present invention makes it possible, on the one hand, to adapt the base and/or fastening element, namely the first molded article, as well as the scraping layer, namely the second molded article, both in the geometries thereof, as well as in the material compositions, in a targeted manner to the technical and material engineering requirements.
• the sealing segment may be a abradable coating for sealing a radial gap between a rotating rotor blade and a housing of a gas turbine, for example.
• the sealing segment may have a honeycomb design.
• sealing segment according to the present invention is produced in accordance with a method as described in detail in the preceding.
• the sealing segment is made of a multiplicity of molded articles, at least two molded articles being produced by powder injection molding.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Ceramic Engineering (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Structural Engineering (AREA)
• Composite Materials (AREA)
• Inorganic Chemistry (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Powder Metallurgy (AREA)
• Sealing Devices (AREA)
• Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

Country Status (5)

Cited By (3)

Families Citing this family (6)

Citations (7)

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• 2006
  • 2006-03-03 DE DE102006009860A patent/DE102006009860A1/de not_active Withdrawn
• 2007
  • 2007-02-27 WO PCT/DE2007/000360 patent/WO2007098739A1/de not_active Ceased
  • 2007-02-27 EP EP07721961A patent/EP1991380A1/de not_active Withdrawn
  • 2007-02-27 CA CA002643568A patent/CA2643568A1/en not_active Abandoned
  • 2007-02-27 US US12/224,681 patent/US20090041607A1/en not_active Abandoned

Patent Citations (7)

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