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WO2023057646A1 - Matériau composite céramique renforcé par des fibres, son procédé de fabrication, pièce constituée d'un matériau composite céramique renforcé par des fibres - Google Patents

Matériau composite céramique renforcé par des fibres, son procédé de fabrication, pièce constituée d'un matériau composite céramique renforcé par des fibres Download PDF

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Publication number
WO2023057646A1
WO2023057646A1 PCT/EP2022/078001 EP2022078001W WO2023057646A1 WO 2023057646 A1 WO2023057646 A1 WO 2023057646A1 EP 2022078001 W EP2022078001 W EP 2022078001W WO 2023057646 A1 WO2023057646 A1 WO 2023057646A1
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Prior art keywords
composite material
fiber
ceramic
fibers
green compact
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Ceased
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PCT/EP2022/078001
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German (de)
English (en)
Inventor
Monika PÜTZ
Bernhard Kanka
Mathias Kunz
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Wpx Faserkeramik GmbH
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Wpx Faserkeramik GmbH
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Priority to EP22801076.5A priority Critical patent/EP4412832A1/fr
Publication of WO2023057646A1 publication Critical patent/WO2023057646A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • 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
    • C04B35/71—Ceramic products containing macroscopic reinforcing agents
    • C04B35/78—Ceramic products containing macroscopic reinforcing agents containing non-metallic materials
    • C04B35/80—Fibres, filaments, whiskers, platelets, or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B18/00—Layered products essentially comprising ceramics, e.g. refractory products
    • C—CHEMISTRY; METALLURGY
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    • 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
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
    • C04B35/111—Fine ceramics
    • 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
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/16—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay
    • C04B35/18—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay rich in aluminium oxide
    • C04B35/185—Mullite 3Al2O3-2SiO2
    • C—CHEMISTRY; METALLURGY
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    • 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
    • C04B35/62605—Treating the starting powders individually or as mixtures
    • C04B35/62625—Wet mixtures
    • C—CHEMISTRY; METALLURGY
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/52—Constituents or additives characterised by their shapes
    • C04B2235/5208—Fibers
    • C04B2235/5216—Inorganic
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/52—Constituents or additives characterised by their shapes
    • C04B2235/5208—Fibers
    • C04B2235/5216—Inorganic
    • C04B2235/522—Oxidic
    • C04B2235/5224—Alumina or aluminates
    • C—CHEMISTRY; METALLURGY
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/52—Constituents or additives characterised by their shapes
    • C04B2235/5208—Fibers
    • C04B2235/5216—Inorganic
    • C04B2235/522—Oxidic
    • C04B2235/5228—Silica and alumina, including aluminosilicates, e.g. mullite
    • C—CHEMISTRY; METALLURGY
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/52—Constituents or additives characterised by their shapes
    • C04B2235/5208—Fibers
    • C04B2235/5252—Fibers having a specific pre-form
    • C04B2235/5256—Two-dimensional, e.g. woven structures
    • C—CHEMISTRY; METALLURGY
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/52—Constituents or additives characterised by their shapes
    • C04B2235/5208—Fibers
    • C04B2235/526—Fibers characterised by the length of the fibers
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/52—Constituents or additives characterised by their shapes
    • C04B2235/5208—Fibers
    • C04B2235/5264—Fibers characterised by the diameter of the fibers
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54—Particle size related information
    • C04B2235/5463—Particle size distributions
    • C04B2235/5481—Monomodal

Definitions

  • Fibre-reinforced ceramic composite material method for its production, component made of a fibre-reinforced ceramic composite material
  • the present invention relates generally to the field of fiber reinforced ceramics. In particular, it relates to the field of oxide ceramics.
  • the present invention relates to a green compact for a fiber-reinforced ceramic composite material, a method for producing and an advantageous use of such a green compact, a component made from such a green compact, a fiber-reinforced ceramic composite material, a method for producing and an advantageous use of such a composite material and a Component made of such a composite material.
  • continuous fibers which can be many tens of centimeters to many meters long
  • short fibers which can only be a few millimeters to a few centimeters long.
  • continuous fibers which can be many tens of centimeters to many meters long
  • short fibers which can only be a few millimeters to a few centimeters long.
  • this usually means fiber bundles, i.e. rovings, in which a large number (up to several thousand) of individual fibers are combined.
  • sections of separated fibers are processed or used, which can be obtained, for example, by means of separation of the individual fibers combined into fiber bundles in commercially available rovings.
  • continuous fiber-reinforced ceramics are known from the prior art, which can have very advantageous thermal and mechanical properties. They are based on fabrics or fabrics made from endless fibers that are embedded in a ceramic matrix. Since continuous fibers are usually very expensive, especially if they consist of a ceramic material, continuous fiber-reinforced ceramics have significant cost disadvantages. Here, woven fabrics made from ceramic fibers are generally even at a disadvantage compared to scrims, as ceramic fibers are brittle and difficult to process into woven fabrics.
  • the ceramic composite materials which are also known in large numbers from the prior art, are significantly more cost-effective and are characterized in that they have short ceramic fibers in particular, which typically have a length of less than 2 millimeters and which are embedded in a ceramic matrix.
  • a slip intended for the production of a ceramic matrix is mixed with short ceramic fibers of the specified length.
  • This slip enriched with short fibers can be sprayed, for example, applied to a negative mold for the production of a component, for example by means of spraying.
  • a green compact according to claim 1 a method for producing a green compact according to claim 31, a use of a green compact according to claim 45, a composite material according to claim 18, a method for producing a composite material according to claim 39, a component made of a composite material according to claim 41 and thermally resistant and electrically insulating components made from a green body or a composite material according to claim 42.
  • the present invention is based on the surprising finding that the thermal and mechanical properties of short-fiber-reinforced ceramics and their green compacts can be significantly improved if individual fibers are placed in the ceramic matrix or their unsintered precursors are embedded.
  • short fiber bundles should preferably not be embedded in the ceramic matrix, rather than isolated fibers.
  • the prior art repeatedly refers to the importance of avoiding short fiber bundles from disintegrating into individual fibers in the production of composite materials as far as possible.
  • a fiber-reinforced ceramic composite material according to the invention has sections of inorganic, preferably oxide-ceramic, fibers that are embedded in an oxide-ceramic matrix.
  • the matrix is formed by particles sintered together.
  • the lengths of the fiber sections have a distribution with a mean length value of at least 6 millimeters, preferably 15 millimeters and particularly preferably over 20 millimeters.
  • the fiber sections are essentially isolated in the matrix or in its unsintered precursor.
  • a composite material according to the invention has a significantly improved fracture-tough failure behavior and a significantly increased thermal shock resistance compared to previously known short-fiber-reinforced ceramic composite materials. This is attributed to the fact that, due to the isolated fiber sections, a spatially essentially constant density of the fiber sections occurs in the green body or in the composite material. If a green body or a composite material is essentially extensive, ie the material thickness transverse to the direction of extension is smaller than the mean length value of the embedded fiber sections, the result is usually a constant areal density of the fiber sections. If a green compact or a composite material essentially has dimensions in all three spatial directions that are larger than the mean length value of the embedded fiber sections, this usually results a constant density of the fiber sections in relation to the volume of the green compact or composite material.
  • a green compact according to the invention and a composite material according to the invention therefore have spatially homogeneous mechanical properties.
  • the orientations of the fiber sections have essentially no preferred direction at least in one plane, and are in particular distributed essentially statistically.
  • the composite materials obtained in this way have particularly isotropic mechanical properties in the fiber plane or transversely to it, i.e. its mechanical strength usually does not have a pronounced preferred direction in this plane.
  • a green body according to the invention also has the same advantageous properties, from which a composite material according to the invention can be obtained, for example by sintering.
  • fiber direction distributions with a clear preferred direction can also be achieved, which can be advantageous for components with a pronounced main direction of stress.
  • the fiber sections in the green compact or in the composite material particularly preferably extend essentially in one plane. In this way, green compacts or composite materials with a thickness of less than one millimeter can be produced, which is particularly advantageous for the production of thin-walled components.
  • the invention is not limited to composite materials or their green compacts with a low material thickness.
  • the material thickness can also be in the range from several millimeters to a few centimeters.
  • fiber distributions can also be realized in which the individual fibers not only essentially extend in one plane, but also across it. This leads to overall more isotropic mechanical properties of the green compact or composite material obtained, which can also be advantageous in individual cases, in particular in the case of greater material thicknesses transverse to the surface direction.
  • a green compact or composite material according to the invention is essentially extensive, which means that its extent in the direction of the surface is significantly greater than transverse to the surface. This means that the thickness of the green compact or composite material is significantly smaller than its extent in the direction of the surface.
  • the isolated inorganic fibers in the composite material according to the invention advantageously have a diameter of between 5 and 20 micrometers, preferably between 8 and 14 micrometers.
  • the composite material obtained and an associated green compact have particularly advantageous mechanical properties if the average length is no greater than 60 mm, preferably no greater than 50 mm. Advantages can also be realized in the production of corresponding green compacts or composite materials. If longer fiber sections are used, it has been found in practice that they tend to form knots, which can be disadvantageous for the manufacturing processes to be used.
  • the average length of the fiber distribution is particularly preferably 25 millimeters ⁇ 10 millimeters, in particular 25 millimeters ⁇ 5 millimeters and particularly preferably 25 millimeters ⁇ 1 millimeter.
  • the bimodal length distribution has a first maximum at 6 millimeters ⁇ 1.5 millimeters, preferably at 6 millimeters ⁇ 1 millimeter. Furthermore, it has proven particularly advantageous if the bimodal length distribution has a second maximum at 25 millimeters ⁇ 3 millimeters, preferably at 25 millimeters ⁇ 1.5 millimeters.
  • the inorganic fibers are ceramic fibers, particularly preferably oxide ceramic fibers.
  • oxide-ceramic fibers which essentially consist of aluminum oxide / Al2O3 or mullite.
  • the manufacturer 3M offers rovings of different thicknesses under the brand name Nextel®, which contain a large number of fibers made of AI2O3 or mullite or mixtures thereof combined into a bundle.
  • Nextel® 610 offers rovings made from fibers that consist of 100% AI2O3. These fibers can be used up to temperatures of 1,100°C.
  • Nextel® 720 offers rovings made from fibers that consist primarily of mullite. These fibers can be used up to temperatures of 1,200°C. Both types have proven themselves for use within the scope of the present invention.
  • the purely mullite fibers of the type R-3840A from the manufacturer Nitivy Co., Ltd. have also proven to be particularly suitable. (Tokyo, Japan) and fibers of the type Altra Flex M80 from the manufacturer Rath AG (Vienna, Austria). Both fiber types can be used at temperatures of up to 1,200°C.
  • Zirconia-doped ceramic fibers have also been found to be advantageous in connection with the present invention. Doping the fibers with zirconium dioxide can increase the creep strength of the fibers.
  • Fibers made from glass or from a mineral material such as basalt can also be used advantageously in the context of the present invention. Although they only withstand significantly lower temperatures, they are significantly cheaper, so that their use allows the realization of significant cost advantages.
  • the inorganic fibers in the composite material have a fiber volume content of at least 10%, preferably 15% or more.
  • the material of the matrix it has proven to be advantageous if the particles present in the matrix and sintered together essentially consist of Al2O3 or mullite.
  • part of the particles consist of Al2O3 and another part of mullite.
  • the particles sintered together also have a proportion of zirconium dioxide particles.
  • Such doping of the matrix with zirconium dioxide can increase the creep strength of the matrix.
  • a particularly high mechanical strength of a composite material according to the invention is observed when the particles in the matrix essentially have a monomodal particle size distribution. It has proven to be advantageous if the average particle size is 2 micrometers or below, preferably 1.5 micrometers or below.
  • the maximum particle size is advantageously 10 micrometers or below, particularly preferably 5 micrometers or below.
  • the particles in the matrix essentially have a bimodal particle size distribution.
  • the particle distribution particularly preferably has a first maximum below 1 micrometer, preferably at about 500 nanometers. Furthermore, the particle size distribution has a second maximum above 4 micrometers, preferably at about 5 micrometers. If there is a bimodal particle size distribution in the matrix, a higher fiber volume content can be achieved in the green compact or composite material according to the invention.
  • both the fibers and the particles of the matrix in the composite material consist essentially of mullite, the result is a particularly high temperature resistance of the composite material according to the invention.
  • These fibers consist of over-stoichiometric mullite, which can contain up to 50 percent by weight of crystallites made of Al2O3. The effect of increased Temperature resistance increases further with increasing mullite content.
  • the result is a particularly high mechanical load-bearing capacity of the composite material in the green state, i.e. the green body.
  • the dried state such a green compact withstands relatively high mechanical loads even without any sintering, specifically for all inorganic fibers to be used within the scope of the present invention.
  • the dried slip regardless of the type of embedded inorganic fibers and in particular in the case of ceramic fibers made of mullite and/or Al2O3, shows only a very slight tendency to disintegrate back into its powdery starting particles under mechanical stress. This is attributed to the fact that mullite shows a certain sintering activity even at low temperatures.
  • An advantageous production process for a green compact according to the invention or a composite material according to the invention therefore also includes the preparation of an aqueous, preferably water-based, slip which contains particles of mullite as sinterable particles or the infiltration of oxide-ceramic fiber sections, which can be present, for example, in the form of a fleece. with such a slip.
  • a composite material according to the invention has similarly advantageous mechanical properties in the dried state in the green state if it has a proportion of fibers made from materials other than mullite, with this proportion being able to be up to 100%.
  • Suitable materials for the embedded fibers are, for example, ceramic materials such as Al2O3, mineral materials such as basalt, or glass. This is discussed in more detail below.
  • a green compact according to the invention whose matrix contains essentially mullitic particles as sinterable particles, has such a high intrinsic strength, at least after drying, that both storage and sintering of the dried green compact is possible without during of sintering, a compressive force must still be applied. It is also possible to use such a green compact even in the unsintered state.
  • beneficial properties are due to the beneficial mechanical properties of the dried mullitic matrix. Even at higher degrees of compression, these reliably prevent relaxation of the compressed green body, which would otherwise lead to damage or even destruction of the matrix.
  • the sintered components of the fiber and the matrix consist of chemically identical material, for example Al2O3 or mullite or a mixture of Al2O3 and mullite, with the mixing ratio of the two components in the latter case also being preferred Matrix and in the fibers agrees.
  • this is not mandatory.
  • the composite material according to the invention which is preferably extensive, has a further layer which is (likewise) extensive and mechanically connected to the composite material.
  • This additional layer can be selected from the following group: a. a layer of a long-fiber roving scrim or long-fiber roving fabric made from a further inorganic, preferably oxide-ceramic fiber, which is embedded in an oxide-ceramic matrix, b. a mat made of an oxide-ceramic short fiber, wherein the mat can be designed in particular as a needle felt, c. a long-fiber non-crimp fabric or long-fiber fabric made from a carbon fiber, which is embedded in an organic matrix, and d. a metal sheet or a grid made of a metallic material or an optionally fiber-reinforced plastic, for example a glass- or carbon-fiber-reinforced plastic.
  • a layer of a long-fiber roving scrim or long-fiber roving fabric which consists of another inorganic, preferably oxide-ceramic, fiber that is embedded in an oxide-ceramic matrix, significantly increases the mechanical strength of the composite material.
  • a layer of a long-fiber roving scrim or long-fiber roving fabric which consists of another inorganic, preferably oxide-ceramic, fiber that is embedded in an oxide-ceramic matrix
  • a still-moist green body of a layer of long-fiber roving fabric or long-fiber roving fabric which consists of another inorganic, preferably oxide-ceramic fiber and is infiltrated with a slip containing sinterable oxide-ceramic particles, is brought into planar contact with a still-moist green body of a composite material according to the invention and allows the resulting composite to dry, resulting in good mechanical adhesion of the infiltrated long-fiber roving fabric or scrim to the green body of the composite material according to the invention.
  • This can be further improved by pressing the two layers together during drying. is about it
  • the sinterable material in the slip of both layers is mullitic, there is a good mechanical connection between the two layers even in the green state of the composite.
  • the combination of a composite material according to the invention with a mat made of an oxide-ceramic short fiber realizes on the one hand an increased thermal insulation effect of the composite material according to the invention developed in this way.
  • an additional mat-like layer made of an oxide-ceramic short-fiber needle fleece has the advantageous property of being thermally insulating and also being able to bind larger amounts of particles that are contained, for example, in smoke.
  • MaftecTM is a mat-shaped material that contains short oxide-ceramic fibers made of Al2O3 and/or mullite. The fibers have a typical diameter of 4 - 5 microns. They are consolidated into a mat by needling.
  • the material ITM FiberMax® has comparable properties.
  • the sinterable material in the slip is also mullitic, a good mechanical connection of the two layers results even in the green state of the composite.
  • a composite is sintered as described above, comprising a green compact according to the invention and a short-fiber mat or a fabric or fabric made from inorganic fibers, a resilient mechanical connection is created between the two layers.
  • a composite material according to the invention with a layer of a long fiber roving scrim or long fiber roving fabric made of glass or carbon fibers, which is embedded in an organic matrix, for example made of a synthetic resin, also improves the mechanical properties of the composite material.
  • the layer comprising glass or carbon fibers can provide mechanical protection for the ceramic composite material and/or stiffen the ceramic composite material against undesired vibrations. The latter point can be particularly advantageous in the case of large, flat components that exhibit a high tendency to vibrate.
  • one or both layers of the resulting composite can have stiffening structures such as ribs or beads.
  • the layer comprising carbon fibers can be applied directly to a composite material according to the invention in the manufacturing process if the organic matrix of the layer comprising carbon fibers has not yet hardened and is therefore still "tacky".
  • the layer comprising carbon fibers can also be positively connected to the composite material according to the invention, for example in that the layer comprising carbon fibers embraces the composite material according to the invention at the edge.
  • a still moist green compact of a composite material according to the invention is molded onto a preferably hardened layer comprising glass or carbon fibers such that the still moist green compact encompasses the layer comprising carbon fibers at the edges. After drying the green compact, the green compact and the layer comprising carbon fibers are mechanically connected to one another.
  • the combination of a composite material according to the invention with a metal sheet or a lattice made of a metallic material or a carbon fiber reinforced plastic also improves the mechanical properties of the composite material.
  • the layer comprising the metal sheet or grid can provide mechanical protection for the ceramic composite material and/or stiffen the ceramic composite material against undesired vibrations. The latter point can be particularly advantageous in the case of large, flat components that exhibit a high tendency to vibrate.
  • one or both layers of the resulting composite can have stiffening structures such as ribs or beads.
  • the layer comprising the metal sheet or grid can be materially bonded to the composite material according to the invention, for example using a suitable adhesive. Furthermore, the layer comprising the metal sheet or grid can also be positively connected to the composite material according to the invention, for example by the layer comprising the metal sheet or grid surrounding the composite material according to the invention at the edge.
  • a still moist green compact of a composite material according to the invention is formed onto a layer comprising a metal sheet or grid in such a way that the still moist green compact encompasses the layer comprising the sheet metal or grid at the edges.
  • the green compact and the layer comprising the metal sheet or grid are mechanically connected to one another.
  • a green compact according to the invention is intended for the production of a fiber-reinforced ceramic composite material which has sections of inorganic, in particular oxide-ceramic, fibers which are embedded in an oxide-ceramic matrix.
  • Many properties of the green compact therefore correspond directly to the properties of the composite material according to the invention described above. To avoid repetition, reference is therefore made to the explanations given there, insofar as these can be transferred to the green compact.
  • the green compact comprises sections of inorganic fibers, in particular oxide-ceramic fibers.
  • the lengths of the fiber sections are distributed with an average length value of at least 6 millimeters, preferably at least 15 millimeters and particularly preferably at least 20 millimeters.
  • the average length of the fiber distribution is preferably 25 millimeters ⁇ 10 millimeters, in particular 25 millimeters ⁇ 5 millimeters and particularly preferably particularly preferably 25 millimeters ⁇ 1 millimeter.
  • the fiber sections are embedded in a slip that includes particles of a sinterable oxide-ceramic material. It is also essential for the invention that the fiber sections are essentially isolated in the slip.
  • the sinterable oxide-ceramic material in the green compact essentially consists of Al2O3 and/or mullite, then a ceramic composite material has; which is obtained by sintering the green body, particularly advantageous thermal and mechanical properties.
  • the slip contains an organic component which inhibits or prevents drying out under ambient conditions.
  • a component can have hygroscopic properties. In this way it can be achieved that a green compact infiltrated with such a slip remains workable/moldable for longer even under ambient conditions.
  • the addition of glycerin to the slip has proven to be advantageous.
  • the green compact can be designed in this way in such a way that it can be stored over a longer period of time in the moist state.
  • moisture-tight packaging of the moist green body is additionally or supportively advantageous.
  • Vapor-tight and advantageously also heat-sealable polymer films have proven to be a particularly suitable packaging material.
  • a green compact according to this advantageous development can be produced at a first location, e.g. under controlled conditions in a production facility provided for this purpose, and then brought to another location as a semi-finished product, where it can be installed, e.g. in a stationary production facility such as an oven. It can also be processed elsewhere as a semi-finished product to produce ready-to-use products. Such semi-finished products are also called from pepregs.
  • glycerin as an organic component to a water-based slip has proven to be particularly advantageous.
  • glycerin significantly inhibits the drying of the slip under normal conditions, which extends the processing time available for the green body with regard to its mechanical deformability.
  • adding glycerin to the slip leads to dried green compacts, which are no longer mechanically deformable, can be made deformable again by rewetting with water. This makes it possible to reduce the requirements for the necessary storage conditions for green compacts according to this development.
  • the slip contains a binder which can advantageously be organic.
  • This binder is set up to harden in the slip and in this way to give the unsintered green body increased mechanical strength.
  • the addition of such a binder to the slip can also lead to an improvement in the abrasion resistance of the dried slip.
  • the addition of such a binder can lead to an increased resistance of the dried slip to moisture.
  • Polyvinyl alcohol has proven to be an advantageous organic binder.
  • Such components can also be used to advantage where sintering conditions only arise when an undesired state of a third component occurs in the vicinity of which the component is arranged.
  • a state which is undesirable per se, can exist, for example, in the event of a fire.
  • a third component can be a battery for an electric vehicle.
  • Such a component can be, for example, a battery cover for such a battery, which is provided, for example, to seal off the passenger compartment thermally and/or in terms of fire protection from the battery in the event of a fire.
  • Such a component can be designed such that the component, which consists of or includes an unsintered green compact according to the invention, is sintered in the event of fire, thereby further improving the already very good fire protection and mechanical properties of the green compact.
  • the orientations of the fiber sections in the green compact according to the invention also essentially have no preferred direction, at least in one plane.
  • the orientations of the individual fiber sections are particularly preferably distributed essentially statistically.
  • the fiber sections also extend essentially in one plane in a preferred embodiment of the green compact according to the invention.
  • the average length of the fiber sections is not greater than 60 mm, preferably not greater than 50 mm, in a preferred embodiment of the green compact according to the invention.
  • a composite material according to the invention with particularly advantageous mechanical and thermal properties is obtained if the fiber sections present in the associated green body are coated with a size.
  • Size is a coating of the individual fibers that gives the individual fibers properties that are advantageous for combining many individual fibers into a roving. This can be, for example, gluing of the individual fibers in the roving in order to improve the cohesion of the roving.
  • the intention can also be to make a surface of the individual fibers that is rough per se smoother.
  • the individual fibers in the roving can be more mobile in relation to one another, as a result of which the roving becomes more flexible.
  • Polymer coatings are often used as sizing, which are applied by spraying the individual fibers or the rovings produced on them with a polymer-containing aqueous solution. Sizes based on the natural substance starch are also known in the prior art.
  • the green compact according to the invention or the composite material according to the invention comprises a fleece, in particular a wet fleece, made from the inorganic fibers.
  • a fleece in particular a wet fleece
  • nonwovens can be produced from many inorganic fibers and can be used advantageously within the scope of the present invention. This also applies in particular to nonwovens made from ceramic (single) fibers.
  • the length of fiber sections for fleece production reference is made to the advantageous or preferred lengths that are specified in general form above in connection with green compacts according to the invention or composite materials according to the invention. These have also proven to be advantageous for nonwoven production.
  • wet nonwovens in particular have proven to be advantageous here. These can be produced, for example, from fiber waste from the production of ceramic fabrics or fabrics made from ceramic fibers. However, chopped ceramic rovings can also be separated into individual fibers, which can then be further processed into wet webs.
  • webs with a thickness of less than one millimeter up to a thickness of many millimeters can advantageously be used.
  • a thickness of between 1 and 5 millimeters has proven particularly advantageous proven, whereby the optimal thickness depends on the respective application.
  • the processing of thinner nonwovens is possible, provided that the mechanical cohesion of the nonwoven can be guaranteed by additional measures.
  • the processing of thicker nonwovens is possible, provided that additional measures can be taken to ensure homogeneous infiltration of the nonwoven with the slip on the one hand and homogeneous drying of the slip on the other.
  • Needled webs can also be produced from inorganic individual fiber sections, in particular from (oxide) ceramic fibers. Such needled webs can also be used advantageously within the scope of the present invention.
  • the fleece is infiltrated with the slip, preferably completely.
  • the inorganic fibers also consist essentially of Al2O3 and/or mullite in a preferred embodiment of the green compact according to the invention.
  • the use of individual fibers from Nextel® 610 or 720 rovings has proven particularly advantageous within the scope of the present invention.
  • the fibers of the type R-3840A from the manufacturer Nitivy Co., Ltd. have also proven to be particularly suitable. (Tokyo, Japan) and fibers of the type Altra Flex M80 from the manufacturer Rath AG (Vienna, Austria).
  • Zirconia-doped ceramic fibers have also been found to be advantageous in connection with the present invention.
  • Polycrystalline or amorphous fibers have also proven to be suitable for use in a composite material according to the invention. Such fibers can be produced, for example, using sol-gel processes.
  • the fibers of this type preferably have a diameter of at least 6 micrometers, preferably 10 micrometers or more.
  • fibers made of alkaline earth metal oxides such as CaO, MgO and ZrO2 and mixtures thereof with SiO2 have proven to be suitable.
  • polycrystalline oxide-ceramic fibers made of Al2O3 or SiO2 or mixtures thereof have proven to be advantageous.
  • inorganic fibers which essentially consist of glass or an inorganic mineral such as basalt has also proven to be advantageous within the scope of the present invention. Reference is made to the previous description of the advantages of composite materials according to the invention, which can be obtained from such green compacts by sintering.
  • At least the particles of the sinterable oxide-ceramic material essentially consist of mullite.
  • a green compact according to the invention has similarly advantageous mechanical properties if it has a proportion of fibers made from materials other than mullite, with this proportion being able to be up to 100%.
  • Suitable materials for the embedded fibers are, for example, ceramic materials such as Al2O3, mineral materials such as basalt, or glass.
  • the inorganic fibers in a preferred embodiment of the green body according to the invention also have a diameter of between 5 and 20 micrometers, preferably between 8 and 14 micrometers.
  • a green compact according to the invention is extensive in the same way as a composite material according to the invention.
  • the green body in a further preferred embodiment of the green body according to the invention also comprises a further layer which is extensive, is mechanically connected to the green body and which is selected from the group: a. Long-fiber scrim or long-fiber fabric made from a further inorganic, preferably oxide-ceramic fiber, which is infiltrated with a slip which comprises particles of a further sinterable oxide-ceramic material, b.
  • Mat made from an oxide-ceramic short fiber c.
  • Long-fiber scrim or long-fiber fabric made of carbon fiber embedded in an organic matrix or d.
  • Sheet metal or grid made of a metallic material or a possibly fiber-reinforced plastic, for example a glass- or carbon-fiber-reinforced plastic.
  • a method according to the invention is provided for the production of a green compact for a fiber-reinforced ceramic composite material, the composite material having sections of inorganic, preferably oxide-ceramic fibers which are embedded in an oxide-ceramic matrix.
  • the method according to the invention has the following method steps: a. providing a fleece of isolated inorganic fibers, b. infiltrating the fleece with a slip comprising particles of a sinterable oxide-ceramic material, and c. Drying of the infiltrated fleece.
  • the further method step of shaping the infiltrated fleece into a three-dimensionally shaped component is provided. This process step is carried out before the infiltrated fleece is dried.
  • the additional method step of mechanically compressing the infiltrated fleece is provided.
  • This process step which can be provided, for example, to improve the surface properties of the dried green compact or a composite material obtained from it by sintering, to increase the fiber volume content in the green compact or composite material or to expel water from the moist green compact, is also carried out before drying the infiltrated fleece carried out.
  • the fiber volume content which is typically 6% by volume in the uncompressed moist green body, can be increased to 12-15% by volume.
  • mechanical compression during drying can also be advantageous in order to ensure that a green compact formed into a three-dimensional component does not lose its impressed shape during drying.
  • the force applied for compression before or during drying is up to lN/mm2.
  • it can be applied to the moist green body from a closed mold or a press.
  • the mechanical connection between the layers can be further improved by mechanical pressing transversely to the fleece layers.
  • the pressing can take place in a punctiform or linear manner, but it is preferably carried out over an area. However, pressing is not absolutely necessary.
  • the individual fleece layer has only a small thickness, which can for example be between 0.5 and 3 millimeters, a green body and, in particular after sintering, a composite material with advantageous mechanical properties can be obtained in this way.
  • At least three infiltrated fleece layers are laminated onto one another, advantageously at least five and preferably at least seven fleece layers.
  • the number of fleece layers laminated on top of one another is practically unlimited, but as a rule it will not exceed 30 layers.
  • a total of 10 individual layers laminated on top of one another has proven to be advantageous for many applications.
  • the surface of the fleece covered with the slip is rolled down with a roller or roller for the purpose of infiltrating the fleece with a slip, in order to also incorporate the slip into the interior of the fleece.
  • a certain amount of flexing work is advantageously carried out by the roll or roller on the fleece.
  • the surface of the fleece is particularly preferably covered with a planar extended grid when it is rolled with a roller or roller, the preferred properties of which have already been discussed.
  • the result is a particularly uniform infiltration of the fleece with the slip.
  • the grid prevents individual fiber sections from detaching from the fleece.
  • a roller is used, the surface of which is covered with a layer of flexible material.
  • a roll or cylinder is used, the surface of which is covered with a layer of an open-pored material that is suitable for absorbing slip in the pores.
  • a roll or cylinder whose surface is covered with a layer of an open-pored sponge made of a flexible material, preferably a polymeric material.
  • a further method step is provided, which is advantageously carried out, for example, for the purpose of infiltrating the fleece with a slip.
  • this process step at least one surface of the fleece is covered with a film that is essentially waterproof.
  • the surface of the fleece is rolled down with a roller or roller as described above when this surface is covered with the film.
  • the film prevents individual fiber sections from detaching from the fleece.
  • the green compact can remain covered with the film even during drying. This also applies when both surfaces of the infiltrated fleece are covered with such a film. Vapor-permeable films made of Tyvek® have proven their worth here.
  • the moist green compact can be heated to accelerate the drying process. Temperatures of up to 80°C have proved their worth. These can be generated in a drying oven, by radiant heat or by microwave radiation.
  • the rate of drying can also be controlled by controlling the humidity of the atmosphere in which the moist green compact is stored for drying.
  • green compacts according to the invention can be rolled up in the moist state.
  • An intermediate layer made of a suitable polymer film, which may also be vapor-permeable, is advantageous here before the roll-up can be, placed on the surface of the areally extended wet green body.
  • the green body and intermediate layer are then wound up together on a suitable bobbin.
  • the wet green body stock thus obtained can remain workable for an extended period of time by being packaged in a vapor-impermeable film, which improves stockability and portability.
  • a movement of the coiled green compact during storage or transport effectively reduces sedimentation phenomena in the moist slip or settling of the slip in the moist green compact.
  • both surfaces of the fleece is covered with a film as described above, there are clear advantages with regard to the handling of the green compact.
  • the still moist green body obtained by the method is packed in a water vapor-tight casing.
  • the moist and therefore still malleable green compact can be transported or stored.
  • the green body in a further method step, which is carried out before or during the drying of the infiltrated fleece, the green body is subjected to a compressive force.
  • the fiber volume content of the dried green compact can be adjusted within wide limits.
  • the dried slip reliably withstands the high elastic restoring forces of those embedded in the dried slip, even in the case of strong compression of the green compact, as may be necessary, for example, to set a high fiber volume content organic fibers, which can in particular also be mullite fibers.
  • a fabric is then produced from an endless fiber bundle made of an inorganic, preferably oxide-ceramic, fiber.
  • this continuous fiber bundle is wound onto the surface of the winding body covered with the fleece.
  • the endless fiber bundle is also infiltrated with a slip that includes particles of a sinterable oxide-ceramic material.
  • the slurries used for the infiltration of fleece and continuous fiber bundles are identical, but they do not have to be.
  • green compacts for composites can be produced from a fleece layer and a scrim layer, which have already been described above as being advantageous.
  • the fiber tension required to produce the scrim can be used in a targeted manner to apply a compressive force to the infiltrated fleece. This can also be used specifically to increase the fiber volume content in the fleece.
  • the green compact produced in this way can be removed from the winding body for further processing while it is still wet.
  • a component is formed from the still wet green compact according to the invention, which can be shaped in particular three-dimensionally.
  • This component can be made, for example, by molding from a negative or positive mold. The shaped component is then dried, for which purpose it advantageously remains on/in the negative or positive mold.
  • a non-infiltrated fleece on the surface of a winding body, in particular to wind up the fleece there.
  • a fabric is then produced from an endless fiber bundle made of an inorganic, preferably oxide-ceramic, fiber.
  • this Endless fiber bundle wound up on the fleece-covered surface of the winding body.
  • the endless fiber bundle is infiltrated with a slip which comprises particles of a sinterable oxide-ceramic material, the infiltration being carried out in excess, so that the infiltrated roving is supersaturated with slip.
  • the slip penetrates the fleece at least superficially and in this way ensures mechanical adhesion of the scrim to the fleece, at least in the dried state.
  • Particularly good results can be achieved with nonwovens whose thickness is less than 3 millimeters, preferably less than 1 millimeter.
  • This method can also be used to produce green compacts for composites from a fleece layer and a scrim layer, which have already been described as advantageous above.
  • a method according to the invention for producing a fiber-reinforced ceramic composite material which has sections of inorganic, preferably oxide-ceramic, fibers that are embedded in an oxide-ceramic matrix has the characteristics of the method according to the invention for producing a green compact. In addition, it has the downstream process step of sintering the (dried) green body.
  • a component according to the invention comprises a fiber-reinforced ceramic composite material or consists of one.
  • the composite material has sections of inorganic, preferably oxide-ceramic, fibers that are embedded in an oxide-ceramic matrix.
  • the composite material is a composite material according to the invention.
  • a use of a component made of a green compact according to the invention and/or a composite material according to the invention as a thermally resistant and electrically insulating component is therefore also within the scope of the present invention.
  • the aforementioned components can in particular be a cover or a housing for a power source, in particular for a mobile power source, and particularly preferably for a battery for an electric vehicle.
  • the aforementioned components can also be, in particular, a sheathing for an electrical conductor, in particular for use in an electric vehicle.
  • a slip is prepared from mullitic particles suspended in water, the proportion by weight of the mullitic particles in the slip being 70-80%.
  • the mullitic particles have a monomodal particle size distribution characterized by D100 ⁇ 10 microns and D50 ⁇ 1.5 microns.
  • a commercially available liquefier from the manufacturer Zschimmer & Schwarz is added to the suspension. The proportion of the added liquefier determines the viscosity of the slip.
  • Ceramic fibers of the type Nextel® 720 from the manufacturer 3M are used for this. After sintering, these fibers consist of 50% mullite and 50% Al2O3. The individual fibers have a diameter of about 10 micrometers.
  • These fibers are offered by 3M in the form of endless rovings in which a large number of individual fibers are combined into fiber bundles. Individual ceramic fibers are obtained by cutting fiber sections with a length of 25 millimeters. In a process known from the prior art, wet webs are obtained from the individual fibers, the thickness of which lies between 0.2 millimeters and 5 millimeters.
  • the mechanical cohesion of a wet fleece can be increased by adding a suitable binder.
  • Typical grammages of the dried wet webs are 25 to 100 g/m2.
  • the fiber volume content of a relaxed, ie not subjected to an external compressive force, wet web is typically 6-7% by volume.
  • a wet mat, as described above, with a thickness of 3 millimeters is completely infiltrated with the slip described above, polyvinyl alcohol with a weight fraction of less than 10% being additionally added as a binder to the slip.
  • the slip is sprayed onto the surface of the wet fleece. Then the surfaces of the wet fleece are covered with a vapor-permeable film.
  • One surface of the covered fleece is rolled down using a roller, which distributes the slip evenly in the wet fleece and results in a homogeneous infiltration. If necessary, a three-dimensional shape is subsequently impressed on the infiltrated wet fleece, for example by molding from a negative mold, or it is placed on a flat surface. It is then fed into a drying chamber and dried there at a temperature between 30°C and 80°C.
  • a first exemplary embodiment of a green body according to the invention is obtained in this way. Due to the mullitic matrix and the binder contained in the slip, the unsintered green body already has good mechanical strength values and a very low tendency to chalking. Chalking tendency is understood to mean the disintegration of the dried matrix when exposed to an external force. For this reason, according to this exemplary embodiment, green bodies that have already been unsintered can be used directly as components for a wide variety of purposes. Examples include components whose practical use can result in such high temperatures that the green body is sintered in situ, namely furnace linings or mechanical and thermal protective shields for covers of power sources such as accumulators, in particular lithium-based accumulators, or fuel cells.
  • the good mechanical properties of the green body also allow mechanical processing of the green body, e.g. to disassemble panels into smaller elements or to cut out complex-shaped components from panels, to trim the edges of three-dimensionally shaped components or to drill holes or cut-outs.
  • Suitable cutting methods are, for example, water jet cutting and laser cutting.
  • a green body according to this first exemplary embodiment is sintered at a temperature of 1200° C.-1250° C. in a chamber or bogie hearth furnace, a composite material according to the invention is obtained.
  • This can advantageously be used, for example, as a mechanically resilient thermal or electrical insulator use with high thermal shock resistance.
  • Application examples are radiation shields, electrical bushings, eg for electrical heating conductors, spacers or fixators for induction conductor technology.
  • green compacts or composite materials according to the invention with improved mechanical properties can be obtained.
  • a green compact according to the first exemplary embodiment is subjected mechanically to a compressive force of 10 N/mm 2 after infiltration with the slip.
  • a vapor-permeable Tyvek® film is placed between the press and the infiltrated wet fleece.
  • the infiltrated wet fleece, which is still pressurized, is then dried as in the first exemplary embodiment.
  • a green compact is obtained with an increased fiber volume fraction of 10-12% by volume. If such a green compact is sintered analogously to the first exemplary embodiment, the composite material obtained has improved mechanical strength values compared to a composite material according to the first exemplary embodiment.
  • wet mats and slips are used as described above and infiltrated according to the method described above.
  • the wet nonwovens have a basis weight of 25g/m2.
  • the slip also contains less than 10% glycerin by weight.
  • Six layers of wet fleece are infiltrated and laid one on top of the other when wet.
  • the top and bottom of the wetlaid pile is covered with Tyvek® film and subjected to a compressive force to increase the fiber volume content to 12-15% by volume.
  • the compressed wet batt stack continues to be subjected to a compressive force until the moisture content in the slip has dropped to such an extent that the slip has sufficient mechanical strength so that the compressive force can be eliminated.
  • a green body according to the invention obtained in this way has improved mechanical properties compared to a green body according to the first exemplary embodiment, in particular it has increased resistance to a cutting torch flame.
  • a composite material according to the invention can be compared to the first and second exemplary embodiment get improved mechanical properties.
  • the composite material obtained has a flexural strength of 35-55 MPa and a modulus of elasticity of 20-30GPa.
  • a composite component is produced from a ceramic short-fiber mat of the type MaftecTM OBM-G MLS-2 or MaftecTM OBM-F MLS-2 with a thickness of 4 millimeters to 20 millimeters and a green compact according to the invention.
  • a ceramic short-fiber mat of the type mentioned is sprayed homogeneously on the surface with the slip described.
  • a moist green compact according to the first exemplary embodiment is placed on this moist short-fiber mat.
  • the resulting material structure is then dried in a drying chamber at 30°C to 80°C as described above. There is very good mechanical adhesion of the wet web to the short-fiber mat. This can be increased if necessary if the damp material structure is subjected to pressure during drying.
  • a material structure obtained in this way can be processed and used like a green compact according to the first exemplary embodiment.
  • the short-fiber mat it includes it also has a very high thermal insulation effect, which makes it advantageous to use it in ovens, for example.
  • the material structure obtained in this way can also be sintered at a temperature of 1200-1250° C. in a chamber or bogie hearth furnace in order to obtain a composite material according to the invention.
  • the sintered wetlaid layer provides a highly effective mechanical barrier between the MaftecTM short fiber batt and an environment where harsh conditions may be present.
  • An example is a furnace lining which, during furnace operation, is constantly hit by scale particles from the interior of the furnace, which would lead to rapid mechanical abrasion of an unprotected MaftecTM short-fiber mat.
  • a green compact according to the invention or a composite material according to the invention with superior mechanical properties is obtained in a fifth exemplary embodiment.
  • a cylindrical winding body with a diameter of 50 millimeters and a length of 150 millimeters is covered with a moist green compact according to the first exemplary embodiment without gaps and in a butt joint.
  • the green wet fleece compact can be compressed in a targeted manner, if necessary, to increase the fiber volume content.
  • the scrim is then cut open along the joint of the green wet fleece, the resulting material structure is placed on a flat surface and then dried in a drying chamber at 30°C to 80°C.
  • the green compact obtained according to this fifth exemplary embodiment Due to the very good mechanical properties of the dried non-crimp fabric, the green compact obtained according to this fifth exemplary embodiment has superior mechanical properties.
  • This also has a composite material obtained from the green compact by means of sintering.
  • a composite material according to this exemplary embodiment is therefore particularly suitable for mechanically stressed structural components, for example for use in chemical reactors.
  • a web of the infiltrated wet nonwoven is wound spirally butt-joined onto the winding body, resulting in a closed covering of the surface of the winding body.
  • another long-fiber scrim is produced on the surface of the winding body covered with a wet fleece, analogously to the fifth exemplary embodiment.
  • the resulting material structure is dried as above, but remains on the surface of the winding body.
  • a green compact of a ceramic pipe is obtained, which is reinforced with an outer reinforcement layer made of an oxide-ceramic long-fiber structure. This green compact can be sintered as described above.
  • a tubular composite material according to the invention is obtained according to a sixth exemplary embodiment.
  • a scrim layer is laid on the winding body analogously to the scrim layer of the fifth exemplary embodiment. At least one layer, in this exemplary embodiment two layers, of a moist, infiltrated wet fleece layer is placed thereon analogously to the fifth exemplary embodiment. As in the fifth exemplary embodiment, a (second) scrim layer is then laid on the surface of the wet fleece layer. The material structure obtained is then cut open as in the fifth exemplary embodiment, on a plane stored on a pad and dried there. A green body according to the invention is obtained with very good mechanical properties in terms of flexural rigidity, which result from the mechanical properties of the outer core layers.
  • the wet fleece layer represents a "neutral fiber" of the resulting sandwich panel.
  • a seventh exemplary embodiment of a composite material according to the invention with outstanding mechanical properties is obtained by sintering such a sandwich plate.

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Abstract

L'invention concerne un matériau composite céramique renforcé par des fibres, un procédé de fabrication ainsi qu'une utilisation avantageuse d'un tel matériau composite et une pièce avantageuse constituée d'un tel matériau composite. Selon l'invention, le matériau composite céramique présente des segments de fibres inorganiques, de préférence de fibres céramiques oxydes, qui sont noyés dans une matrice céramique oxyde formée de particules agglomérées par frittage. L'invention concerne en outre une ébauche crue pour un tel matériau composite céramique renforcé par des fibres, un procédé de fabrication ainsi qu'une utilisation avantageuse d'une telle ébauche crue et un pièce avantageuse obtenue à partir d'une telle ébauche crue.
PCT/EP2022/078001 2021-10-08 2022-10-08 Matériau composite céramique renforcé par des fibres, son procédé de fabrication, pièce constituée d'un matériau composite céramique renforcé par des fibres Ceased WO2023057646A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2848599A1 (fr) * 2013-09-12 2015-03-18 Universität Bayreuth Matériau composite de céramique d'oxyde et préforme de fibres pour sa production
WO2017220727A1 (fr) * 2016-06-22 2017-12-28 Universität Bayreuth Matériaux composites céramiques et leur procédé de préparation

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4666645A (en) * 1984-04-20 1987-05-19 United Technologies Corporation Method for forming fiber reinforced composite articles
DE10043666C1 (de) * 2000-08-29 2001-10-25 Fraunhofer Ges Forschung Verfahren zur Herstellung eines keramischen Dämmstoffes
JP4730495B2 (ja) * 2001-05-25 2011-07-20 イビデン株式会社 触媒コンバータ用保持シール材及びその製造方法、触媒コンバータ
JP2013543072A (ja) * 2010-05-17 2013-11-28 ゼネラル・エレクトリック・カンパニイ セラミックマトリクス複合材構造体、それを用いて形成される構成要素、および製造方法
JP6396938B2 (ja) * 2016-03-30 2018-09-26 東京窯業株式会社 リチウム電池の正極活物質用熱処理容器

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2848599A1 (fr) * 2013-09-12 2015-03-18 Universität Bayreuth Matériau composite de céramique d'oxyde et préforme de fibres pour sa production
WO2017220727A1 (fr) * 2016-06-22 2017-12-28 Universität Bayreuth Matériaux composites céramiques et leur procédé de préparation

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