Abstract: A precursor material is disclosed. This precursor material is comprised of at least about 16 weight percent of beta-sialon, from about 54 to about 28 weight percent of alumina, from about 0 to about 8 weight percent of aluminum nitride, from about 0 to about 25 weight percent of silicon nitride, and from about 30 to about 24 weight percent of free silicon.

Abstract: A sintered ceramic composite body is manufactured by preparing a powdery mixture composed of a base material composed of either one of oxide ceramic such as alumina, mullite, magnesia, or the like, and nonoxide ceramic such as silicon nitride, sialon, or the like, and a reinforcement material composed of particles or platelet particles of silicon carbide which have a size ranging from 5 to 20 .mu.m, the particles of silicon carbide being contained at a volume ratio ranging from 3 to 50%. The platelet particles have a maximum diameter ranging from 5 to 50 .mu.m and a thickness which is 1/3 or less of the maximum diameter. The powdery mixture is molded into a shaped product, which is then sintered in a temperature range from 1,400.degree. to 1,900.degree. C. for the base material which is composed of oxide ceramic or in a temperature range from 1,500.degree. to 2,000.degree. C. for the base material which is composed of nonoxide ceramic.

Abstract: A porous refractory carbide with a large specific surface area is disclosed. The refractory carbide has a skeleton of metallic or metalloid refractory carbide and has a bimodal open porosity with a group of pores of 1 to 100 microns and a group of pores smaller than 0.1 micron.

Abstract: A ceramic sliding member is formed of sintered silicon nitride material which contains Si.sub.3 N.sub.4 as the major component and further contains Y, Mg and Ce, the Y content being 2 to 20% by weight in terms of Y.sub.2 O.sub.3, the Mg content being 0.1 to 0.9% by weight in terms of MgO, and the Ce content being 1 to 10% by weight in terms of CeO.sub.2.

Abstract: A clamping tool having a clamping head, a cylinder member coupled to an edge portion of the clamping head, a ram member coupled to and movably arranged within the cylinder member, a first die member coupled to the clamping head, and a second die member arranged to face the first die member and movable by the ram member toward and away from the first die member, wherein at least the clamping head is formed of a composite material prepared by dispersing at least one reinforcing material selected from the group consisting of ceramic fibers, ceramic whiskers and ceramic particles into a matrix metal consisting essentially of an aluminum alloy or a magnesium alloy. The clamping head is light, has a high Young's modulus, exhibits a high fatigue resistance, and is free from cracking and scattering of the cracked pieces. The clamping tool permits an operator to operate the clamping tool under a safe environment, and lessens the burden given to the operator, leading to an improved working efficiency.

Abstract: A method for producing a self-supporting ceramic composite body having a negative pattern which inversely replicates the positive pattern of a parent metal precursor having thereon a positive pattern section which is emplaced in conforming engagement with a bed of conformable filler. The parent metal precursor, which also has a non-replicating section, is melted and reacted with an oxidant to form a polycrystalline oxidation reaction product which grows primarily only from the positive pattern section of the parent metal precursor and through the filler. The molten parent metal is drawn through the growing polycrystalline material and oxidized at the interface between the oxidant and previously formed oxidation reaction product. The reaction is continued for sufficient time to at least partially embed the filler within the oxidation reaction product and form the ceramic composite body containing a negative pattern which inversely replicates the positive pattern of the parent metal precursor.

Abstract: A crosslinkable composition suitable for use as an infiltrant or as a binder for ceramic powders, such as silicon carbide and/or silicon nitride, in a formulation intended to be injection molded or extruded comprises about 40-70% by weight of a low molecular weight polysilazane, about 15-35% by weight of a medium molecular weight polysilazane, and about 5-30% by weight of an unsaturated organic or organosilicon compound containing at least two alkenyl groups. A preferred unsaturated compound is methylvinylcyclosilazane.

Abstract: A method of producing a refractory material of the non-shaped type is disclosed. Refractory aggregates and a binder are mixed ensuring cohesion by chemical bonding. The mixture is shaped and fired. A charge comprising refractory particles of a polymodal granulometric distribution is mixed with a liquid binder consisting of a mixture in an aqueous medium of polysilicate-based mineral polymers and a mineral polymer comprising sialate groups. The paste obtained is shaped and after hardening of the mixture at a temperature between ambient temperature and 200.degree. C., the hardened mixture is brought to a temperature between 200.degree. and 1300.degree. in order to obtain a refractory material having high mechanical properties, high resistance to thermal shock and resistance to chemical corrosion.

Abstract: A method of infiltration forming silicon carbide bodies having an improved surface finish comprises, infiltrating a porous carbonaceous preform with molten infiltrant to form a silicon carbide body. The body is heated in an inert atmosphere or vacuum to a temperature where the infiltrant is molten while the body is positioned in contact with an infiltrant wicking means. Preferably, the wicking means has infiltrant wicking capillaries at least as large as the infiltrant wicking capillaries in the body. Capillary force draws excess infiltrant on the surface of the body from the surface leaving the reaction formed silicon carbide body with a surface substantially free of excess infiltrant droplets.

Abstract: A crosslinkable preceramic composition suitable for use as an infiltrant for porous ceramics, such as fiber-reinforced ceramic composites, comprises about 75-99% by weight of a low molecular weight polysilazane and about 1-25% by weight of an unsaturated organic or organosilicon compound containing at least two alkenyl groups, preferably methylvinylcyclosilazane. Infiltration of composites with the infiltrant can be accomplished by melt or solution infiltration, and the subsequent pyrolysis of the infiltrant results in the formation of a densified ceramic article having improved strength.

Abstract: A ceramic fiber-ceramic composite filter having a support composed of ceramic fibers, preferably texturized, a carbonaceous layer thereover, and a silicon carbide coating over the carbonaceous layer and coated on substantially all of the fibers. A strong, tough, light weight filter is achieved which is especially useful in high temperature gas environments.

Abstract: A method is provided for producing a self-supporting ceramic body comprising a polycrystalline material comprised of the oxidation reaction product of a parent metal and having therein one or more channels which inversely replicate the geometry of a configured fugative metal. The method includes providing an assembly of the configured fugitive metal and the parent metal, optionally including a bed of permeable filler, and heating the assembly to form a body of molten parent metal. The molten parent metal is oxidized under selected conditions to grow the polycrystalline material to engulf the configured fugitive metal (and to infiltrate the filler, if the filler is present) and to cause the fugitive metal to disperse into the engulfing polycrystalline material thereby leaving behind as the one or more channels the space formerly occupied by the configured fugitive metal.

Abstract: A sintered ceramic composite body is manufactured by preparing a powdery mixture composed of a base material composed of either one of oxide ceramic such as alumina, mullite, magnesia, or the like, and nonoxide ceramic such as silicon nitride, sialon, or the like, and a reinforcement material composed of particles of silicon carbide which have a size of 1 .mu.m or less and a size ranging from 5 to 20 .mu.m, or have a size of 1 .mu.m or less and platelet silicon carbide particles having a maximum diameter ranging from 5 to 50 .mu.m and a thickness which is 1/3 or less of the maximum diameter, the particles of silicon carbide being contained at a volume ratio ranging from 10 to 50%. The powdery mixture is molded into a shaped product, which is then sintered in a temperature range from 1,400.degree. to 1,900.degree. C. for the base material which is composed of oxide ceramic or in a temperature range from 1,500.degree. to 2,000.degree. C. for the base material which is composed of nonoxide ceramic.

Abstract: Improved ceramic compositions are provided that are useful in the formulation of microwave susceptors as well as the susceptor articles fabricated therefrom. The novel compositions include a binder and a microwave absorbing material of compounds selected from the group consisting of carbides, borides, or nitrides which compositions are sintered at temperatures above about 800.degree. C.

Abstract: A high-density and high-strength .beta.-type silicon carbide sintered body, in which crystal grains are made uniform and fine by adjusting the compounding ratio of the sintering aid and further taking a special means at the sintering step while suppressing the inclusion of .alpha.-SiC into the starting powder as far as possible during the production of the silicon carbide sintered body.

Abstract: A process for preparing silicon carbide by carbothermal reduction which includes transporting, in a gaseous medium, a particulate reactive mixture of a silica source and a carbon source through a reaction zone. The heating rate of the atmosphere within the reaction zone is such that substantially all of the reactive mixture is heated at a heating rate of at least about 100.degree. C./second until an elevated temperature of at least 1800.degree. C. is reached. Either (1) carbon monoxide is added to the reaction zone or (2) a carbon monoxide level in the reaction is achieved in order to provide at least about 30 mole percent of the gases exiting the reaction zone to achieve a higher yield of silicon carbide.

Abstract: A microwave absorbing heater comprising a porous body containing silicon oxide and having a porosity of 40 to 95%.A microwave absorbing heater may be formed of a porous body having a porosity of 40 to 95% and composed of an inorganic electrical insulating material, and a silicon carbide film formed on the surface thereof.Since the microwave absorptivity is high, the dissipation of water from a heated object is easy and the heat dissipation is small, the heating efficiency is great. The thermal shock resistance is also high.

Abstract: A high-toughness ZrO.sub.2 sintered body having a stress-induced transformation ratio of 25% or more, which consists essentially of 40-90 volume % of ZrO.sub.2 containing 0.1-3 mol % of Nd.sub.2 O.sub.3 and 0.5-3.5 mol % of Y.sub.2 O.sub.3 as stabilizers of the crystal structure of ZrO.sub.2, and 10-60 volume % of at least one of Al.sub.2 O.sub.3, SiC, TiC, B.sub.4 C and TiB.sub.2.

Abstract: Preceramic polymer dispersions which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by dispersing about 0-3 parts by weight of aluminum-silicon eutectic, about 0-4 parts by weight of silicon carbide, about 1.5-5 parts by weight of silicon boride, and about 0.4-5 parts by weight of silicon metal in a solution of an organoborosilazane polymer in an organic solvent, the organoborosilazane polymer being the product obtained by reacting about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polysilazane.

Abstract: High purity silicon carbide parts for a heat treating apparatuses for semiconductors; composed mainly of .alpha.-type silicon carbide and silicon; characterized in that a particle sizes of the .alpha.-type silicon carbide crystals composing the high purity silicon carbide parts are not larger than 44 .mu.m; a weight mean particle size of the .alpha.-type silicon carbide crystals is in a range from 2 to 25 .mu.m; high purity silicon is filled up among the particles of the .alpha.-type silicon carbide crystals; and a content of iron as an impurity element contained in the high purity silicon carbide parts is not larger than 5 ppm.

Abstract: A process for producing silicon carbide platelets having a size of 20 .mu.m or less, and the platelets so produced. The process comprises reacting particles of a non-graphitizable form of hard carbon containing 0.5-1.5% by weight of aluminum and at least 0.2% by weight of iron (preferably anthracite coal, most preferably Pennsylvania anthracite), with silica or a silica precursor at a temperature in the range of 1800.degree.-2100.degree. C. under an inert atmosphere. If the carbon contains 0.2-1.0% by weight of iron, 0.1-10% by weight of boron, relative to the weight of SiO.sub.2, is added (if not already present). In the invention, 0.1-10% by weight of the reaction mixture of alpha silicon carbide particles having a size of 5 .mu.m or less are added to the reaction mixture to control the size of the platelets so that a majority have a size of less than 20 .mu.m. The carbon is in the form of particles of less than 50 .mu.

Abstract: A method of preparing preceramic SiC fibers having a very low oxygen content by forming fibers from a solution of a polycarbosilane and a vinylic SiC precursor in a mutual volatile solvent, heating fibers in an oxygen-free inert atmosphere to effect a cross-linking reaction therebetween. Also disclosed is a method of preparing SiC fibers having superior high temperature properties and a very low oxygen content comprising heating the above-described cross-linked preceramic fibers in an inert atmosphere substantially free of oxygen for a time and at a temperature sufficient to pyrolyze the cross-linked fibers to SiC fibers. The disclosure also describes the novel fibers produced by the above-described methods.

Abstract: Metal carbides can be formed by the pyrolysis of a composition comprising metal and carboxylic acid residues bonded therein, the composition being substantially free of extraneous carbon and also having metal moieties that are not in the substituent position. Dicarboxylic acids, for example, can be reacted with either metal alkoxides or metal halides to form an oligomer or polymer which can be calcined to the metal carbide. Alternatively, a metal alkoxide can be reacted with a monocarboxylic acid to form a metal alkoxide carboxylate which can be heated to the metal carbide. Finally, a metal carboxylate can be heated to form the desired metal carbide.

Abstract: A silicon carbide membrane suitable as a masking material in X-ray lithography is provided, which is free from the defects in the prior art products prepared by the chemical vapor deposition method such as pinholes and instability against irradiation with high-energy beams. The silicon carbide membrane is prepared by the deposition of a silicon carbide film on a silicon substrate by the method of sputtering using silicon carbide as the target material under specified atmospheric conditions, substrate temperature and power density on the target and removing the silicon substrate leaving the peripheral zone to serve as a frame.

Abstract: Preceramic compositions which are useful in providing protective ceramic coatings on carbon/carbon composites, graphite, and other carbonaceous materials are prepared by dispersing about 0.4-1.5 parts by weight of silicon carbide, silicon nitride, or a mixture thereof in a solution of one part by weight of a polysilazane in about 2.5-10 parts by weight of a liquid aromatic hydrocarbon.

Abstract: This invention relates to the preparation of thermally stable, substantially polycrystalline silicon carbide ceramic fibers derived from a polycarbosilane resin. The unexpected thermal stability of these fibers is achieved by the incorporation of boron prior to ceramification.

Abstract: The subject invention relates to a coated reinforcement material comprising a SiC reinforcement having a coating of at least three layers, wherein the layers are alternately A-material layers of the general formula:Al.sub.x O.sub.y N.sub.zwherein x is up to about 60 atomic % of the coating;y is from about 20 atomic % to about 55 atomic % of the coating; andz is from about 5 atomic % to about 45 atomic % of the coating, with the proviso that x+y+z=100, and B-material layers comprising a metal alloy, such that the first and last layers of the coating are A-material layers. The invention further relates to a high strength, high temperature performance composite containing the above-specified coated reinforcement.

Abstract: A molded body formed of a silicon nitride-based ceramic containing Si and N and optionally O, C and/or a metal. The ceramic is formed from a polysilazane. A molded body may be a composite body which is composed of a matrix of the ceramic and a reinforcing material such as powder or fiber embedded within the matrix or which is composed of ceramic powder bound with a binder formed of the silicon nitride-based ceramic.

Abstract: Substantially dense, void-free ceramic-metal composites are prepared from components characterized by chemical incompatibility and non-wetting behavior. The composites have a final chemistry similar to the starting chemistry and microstructures characterized by ceamic grains similar in size to the starting powder and the presence of metal phase. A method for producing the composites requires forming a homogeneous mixture of ceramic-metal, heating the mixture to a temperature that approximates but is below the temperature at which the metal begins to flow and pressing the mixture at such pressure that compaction and densification of the mixture occurs and an induced temperature spike occurs that exceeds the flowing temperature of the metal such that the mixture is further compacted and densified. The temperature spike and duration thereof remains below that at which significant reaction between metal and ceramic occurs. The method requires pressures of 60-250 kpsi employed at a rate of 5-250 kpsi/second.

Abstract: In a method of manufacturing a sintered ceramic material using the heat generated in a thermit reaction as a heating source, a pre-heating is applied preceding to the sintering step or a mixture comprising: (A) at least one ceramic powder, (B) at least one non-metallic powder selected from the group consisting of carbon, boron and silicon, and (C) a metal powder and/or a non-metallic powder other than the above-mentioned (B) is used. Homogeneous and dense sintered ceramic material or sintered composite ceramic material can be obtained by this method, and the fine texture thereof, and the phase constitution, the phase distribution and the like of the composite ceramic phase can be controlled sufficiently.

Abstract: Silicon carbide fibers which are derived from oligomeric and/or polymeric precursors are modified and strengthened in annealing the silicon carbide fiber at temperatures in excess of 800.degree. C. under a nitrogen atmosphere in the presence of carbon particles. The modified fibers can be used to make ceramic, metal, and plastsic composites.

Abstract: This invention provides a carbon-containing ceramic composite for molten non-ferrous metal, the composite being a sintered ceramic body to be used in contact with molten non-ferrous metal, the sintered body containing an aggregate of silicon carbide and/or silicone nitride, the sintered body being characterized in that it comprises,(a) 100 parts by weight of the aggregate,(b) 5 to 45 parts by weight of flake graphite, and(c) boron carbide in an amount of 10 to 40% by weight based on the flake graphite.

Abstract: A sintered silicon nitride-silicon carbide composite material is provided comprising a matrix phase of silicon nitride and silicon carbide where silicon carbide grains having an average diameter of not more than 1 .mu.m are present at grain boundaries of silicon nitride grains and silicon carbide grains having a diameter of several nanometers to several hundred nanometers, typically not more than about 0.5 micrometers, are dispersed within the silicon nitride grains and a dispersion phase where (a) silicon carbide grains having an average diameter of 2 to 50 .mu.m and/or (b) silicon carbide whiskers having a short axis of 0.05 to 10 .mu.m and an aspect ratio of 5 to 300 are dispersed in the matrix phase. A process for the production of the composite material is also provided.

Abstract: Fiber-reinforced ceramic matrix composites incorporating a glass-ceramic matrix of lithium aluminosilicate composition in which is disposed a fiber reinforcement phase including at least one layer of unidirectionally oriented fibers (e.g. SiC), the matrix further comprising a whisker reinforcement phase selected from the group of SiC, alumina, HfC and Si.sub.3 N.sub.4, the whiskers imparting substantially improved transverse modulus of rupture strength and interlaminar shear strength to the composite.

Abstract: A composite is produced by admixing a matrix-forming material with organic binding material, forming the resulting mixture into a tape, disposing a layer of fibrous material between at least two of the tapes to form a layered structure, laminating the layered structure, heating the layered structure to remove organic binding material and hot pressing the resulting porous structure to form a composite containing a layer of fibrous material.

Abstract: In order to obtain a reinforcement texture made essentially of silicon compound based ceramic fibers in the production of a composite material, the fibers are spun from a ceramic presursor in the molten state, after which they are submitted to a partial cross-linking in view of making the fibers infusible. The cross-linking of the fibers in the precursor in the infusible state is continued and, while they are maintained in the organic state, the cross-linked fibers are submitted to one or several textile-forming operations, such as weaving, layering, needling . . . in order to arrive at the multidirectional texture. Then, the texture is submitted to a heat treatment by pyrolysis to induce the ceramic state of the fibers and so obtain the required texture, which is essentially made of ceramic fibers having a silicon compound base, in particular silicon carbide.

Abstract: An aqueous plastic composition of an inorganic powder which per se has substantially no plasticity which comprises: the inorganic powder and a polysaccharide of natural origin.The molding and sintering of the plastic composition provide a sintered body of high mechanical strength and dimensional accuracy.

Abstract: A MgO/SiC composite material in which SiC particles with nano-meter order in size are dispersed within MgO matrix grains can be prepared by hot-pressing the mixture of fine MgO and SiC powders. Addition of SiC particles in the range of 5 volume percent to 50 volume percent to the MgO matrix increased remarkably the fracture strength and the hardness in a nanometer-order structure of the composite.

Abstract: A method is provided for preparing preceramic polymers and silicious ceramic materials which derive therefrom. The preceramic polymers are polysiloxanes which are synthesized by catalytically activating Si-H bonds in a hydridosiloxane starting material and replacing the activated hydrogen atoms with non-hydrogen substituents. These preceramic polysiloxanes are pyrolyzed in a selected atmosphere to give the desired ceramic product. Ceramic products which may be prepared by this technique include silica, silicon oxynitride, silicon carbide, and metal silicates.

Abstract: Essentially infusible/insoluble crosslinked polysilazanes, well adapted for pyrolysis and conversion into silicon carbide and/or silicon nitride ceramic materials, are produced by intimately contacting a fusible and organic solvent soluble polysilazane starting material with an effective crosslinking amount of gaseous triflic acid, CF.sub.3 SO.sub.3 H, and in which starting polysilazane the organic radicals directly bonded to silicon atoms are saturated and/or aromatic hydrocarbon radicals and such starting polysilazane being devoid of hydrogen atoms directly bonded to a silicon atom.

Abstract: A sliding material made of a sintered silicon carbide having open pores of a three dimensional network structure, the open pores present at a rate of 5 to 40 percent by volume, with the open pores being impregnated with a lubricant, where the lubricant is selected from a group of lubricants consisting of fluorine-type oils and silicone-type oils.

Abstract: This invention relates to the preparation of highly densified ceramic bodies by the pyrolysis of a mixture comprising a preceramic borosiloxane, silicon carbide powder, a curing agent for the borosiloxane, a crosslinking agent for the borosiloxane and, optionally, additional components to facilitate sintering. Such highly densified ceramic bodies can be prepared by sintering under pressure or by a pressureless sintering process.

Abstract: A ceramic matrix composite article having a varying thickness is fabricated by a process wherein multiple prepreg sheets comprising reinforcing fibers and powdered matrix material are stacked to provide a multi-layer prepreg stack wherein, through each cross-sectional dimension perpendicular to the plane of the sheets, the number of prepreg sheets contributing to the aggregate sheet thickness of the stack varies in proportion to the relative thickness desired in the layered article. The stack may consolidated to a composite article with a smoothly varying thickness profile without undue fiber breakage or ply wrinkling in the composite structure consolidated into a composite article having a smoothly varying thickness profile with reduced internal fiber bowing or breakage. Preferably, the exterior surfaces of the article comprise long, substantially continuous fibers and are free of ply drops.

Abstract: A process for producing a refractory material having the form TB.sub.o, e.g. zirconium nitride (ZrN), includes a first step of mixing a first salt having the form TX.sub.n, e.g. zirconium tetrachloride (ZrCl.sub.4) and a second salt having the form A.sub.m B, e.g. lithium nitride (Li.sub.3 N) in a ratio of n/m in a container. The process also includes a second step of igniting the mixture of the first and second salts, e.g. ZrCl.sub.4 and Li.sub.3 N, whereby the refractory material, e.g. ZrN, is produced along with byproducts having forms nAX and (n/m-o)B, e.g. 4LiCl and (1/6)N.sub.2, respectively. The process further includes a third step of separating the refractory material from the byproducts by solvent extraction. The stoichiometric ratio of the second salt to the first salt is n/m, e.g. 4/3. T is selected from the group consisting of transition metals, e.g. zirconium, and tetrelides, i.e. carbon, silicon, germanium, tin and lead.

Abstract: A method and apparatus are provided for producing a product comprising a carbide compound, such as for example silicon carbide. A reactor is provided which has a chamber defined therein which is divided into a combustion zone and a reaction zone. A combustible mixture is injected into the combustion zone and accordingly combusted to form hot combustion products. At least one reactant (i.e. silane) is injected at the boundary between the zones so as to be carried into the reaction zone by the combustion products and react to form raw product comprising the carbide compound. The raw product can be purified by subsequent processing to remove oxygen and convert by-products to the desired carbide compound. The product of the invention has a low level of impurities and is made up of submicron, highly uniform particles. This makes the product particularly useful for fabrication of sintered ceramic parts.

Abstract: The invention relates to a method for producing ceramic composites obtained by oxidation of a parent metal to form a polycrystalline ceramic material by providing a filler having a coating of a silicon source on at least a portion of the filler different in composition from the primary composition of the filler, said silicon source possessing intrinsic doping properties. A body of molten parent metal, adjacent a mass of the filler material, reacts with an oxidant to form an oxidation reaction product which infiltrates the adjacent mass of filler, thereby forming the ceramic composite.

Abstract: A process is provided for obtaining an article which is made of a carbon-containing composite material and which is protected against oxidation. The composite material, which is obtained by densifying a porous fibrous texture with a matrix and which exhibits a residual internal porosity, is impregnated under a vacuum with an alkaline compound in a liquid solution. The article is dried and heat-treated at a temperature sufficient to cause the alkaline compound to line the surfaces of the internal pores, thereby constituting the residual porosity and forming a continuous auto-cicatrizing internal protective coating. An additional external protective layer comprised of a wear- and oxidation-resistant material may be applied.

Abstract: The invention relates to a method of fabrication in the powdered state of ceramic compounds formed between a metalloid and a refractory metal, characterized in that it involves the following steps:a) said metalloid is caused to react with a reducing metal within a liquid bath constituted at least partly by a fused salt of said reducing metal in order to obtain a saltlike intermediate compound which combines said reducing metal and the metalloid, in solution in said bath,b) a reducible salt of said refractory metal is then injected into said bath in a divided form which is directly distributed throughout the bath in order to produce said powder by reaction of the reducible salt with said intermediate compound of the reducing metal.

Abstract: Preceramic compositions which have particular utility in providing protective ceramic coatings on carbon/carbon composites, graphite, carbon fibers, and other normally oxidizable materials are prepared by mixing about 0.25-20 parts by weight of a trialkoxy-, triaryloxy-, or tri(arylalkoxy)boroxine with one part by weight of a polycarbosilane in an organic solvent.

Abstract: The present invention relates to a method of forming ceramic matrix composite bodies comprising a parent metal reacting with an oxidant to produce an oxidation reaction product which infiltrates a loose unbonded mass or a preform comprising a filler material mixture. Specifically, the filler material mixture used in the method of the present invention comprises a material having varying compositions, sizes and/or shapes of filler material within the mass or preform. By utilizing a filler possessing varying compositions, sizes and/or shapes, enhanced packing of the filler material is achieved which may result in improved properties, such as erosion resistance, corrosion resistance, etc. Further, the use of filler material containing varying sizes and/or shapes may also enhance the growth rate of oxidation reaction product, thereby reducing processing times for formation of the resultant ceramic composite body.