Abstract: A sintered material includes a first material and a second material, wherein the first material is partially stabilized ZrO2 in which 1 to 90 volume % of Al2O3 is dispersed in crystal grain boundaries or crystal grains, the Al2O3 is a grain having a grain size of less than or equal to 1 ?m, and the second material is at least one compound selected from a group consisting of a carbide, a nitride, and a carbonitride, and 5 to 95 volume % of the second material is included in the sintered material.

Abstract: A method is provided in which a lower box comprising a base, walls that surround the base and an open side, and an upper box comprising a cover, walls that surround the cover and an open side are provided. One or more objects are arranged on the base of the lower box. The object(s) are covered with the upper box such that the open side of the upper is oriented towards the base of the box, the walls of the upper box are arranged on the base of the lower box and a gap is formed between the walls of the upper box and the walls of the lower box. A powder material is introduced into the gap in order to form an assembly having an interior. The powder material provides a mechanical obstacle to gas exchange between the interior and the environment. This assembly is then heat treated.

Abstract: A silicon nitride substrate comprises a substrate comprising a silicon nitride sintered body, and a plurality of granular bodies containing silicon and integrated to a principal surface of the substrate, wherein a plurality of needle crystals or column crystals comprising mainly silicon nitride are extended from a portion of the granular bodies. A brazing material is applied to a principal surface of the substrate, and a circuit member and a heat radiation member are arranged on the applied brazing material, and bonded by heating. Because of a plurality of granular bodies integrated to the principal surface of the substrate, and a plurality of the needle crystals or the column crystals extended from a portion of the granular bodies, a high anchor effect is produced so that the circuit member and the heat radiation member are firmly bonded to the silicon nitride substrate.

Abstract: The disclosure provides novel graphene-reinforced ceramic composites and methods for making such composite materials.

Abstract: The invention concerns a sintered ceramic component of silicon nitride or sialon suitable as rolling element in a bearing and a manufacturing method for making such ceramic components. The ceramic component has high density and a homogeneous and fine microstructure, giving the component excellent mechanical properties. Manufacturing of the sintered ceramic component by SPS is cost-effective and rapid.

Abstract: Composite bodies made by a silicon metal infiltration process that feature a silicon intermetallic, e.g., a metal silicide. Not only does this give the composite material engineer greater flexibility in designing or tailoring the physical properties of the resulting composite material, but the infiltrant also can be engineered compositionally to have much diminished amounts of expansion upon solidification, thereby enhancing net-shape-making capabilities. These and other consequences of engineering the metal component of composite bodies made by silicon infiltration permit the fabrication of large structures of complex shape.

Abstract: A composite article having a body including a first phase that includes a nitride material, a second phase that includes a carbide material, and a third phase having one of an amorphous phase material with a nitrogen content of at least about 1.6 wt % or an amorphous phase material comprising carbon.

Abstract: A silicon nitride cutting tool comprising a sintered product is disclosed. The sintered product comprises silicon nitride, at least one rare earth element compound, and a magnesium compound. The silicon nitride cutting tool further comprises a surface region and an inside region comprising the sintered product with varying content ratios of component compounds to provide enhanced wear and fracture resistance.

Abstract: A process for manufacturing a sintered ceramic composite, based on silicon nitride and ?-eucryptite, includes a step of producing a first powder blend, consisting of a powder of silicon nitride in crystalline form and a powder of a first lithium aluminosilicate in crystalline form, the composition of which is the following: (Li2O)x(Al2O3)y(SiO2)z, the lithium aluminosilicate composition being such that the set of molar fractions (x,y,z) is different from the set (1,1,2).

Abstract: Composite materials composed of cubic boron nitride (cBN) and a matrix component of various ceramic oxides, nitrides, and solid solutions of matrix materials as well as whisker reinforcements. Methods of manufacture and their use in high performance machining of ferrous metals are also claimed and disclosed.

Abstract: Composite bodies made by a silicon metal infiltration process that feature a silicon intermetallic, e.g., a metal silicide. Not only does this give the composite material engineer greater flexibility in designing or tailoring the physical properties of the resulting composite material, but the infiltrant also can be engineered compositionally to have much diminished amounts of expansion upon solidification, thereby enhancing net-shape-making capabilities. These and other consequences of engineering the metal component of composite bodies made by silicon infiltration permit the fabrication of large structures of complex shape.

Abstract: The invention relates to a ceramic product, manufactured from a mixture made of natural and/or synthetic inorganic non-metal raw materials, at least one binder and optionally further additives. In order to provide ceramic products allowing for disadvantages known from the prior art to be eliminated, at least with respect to corrosion and erosion, it is proposed that the ceramic products are manufactured from a mixture comprising a) at least 10% by weight (based on the weight of all solids of the mixture) oxidic components, b) 0.05 to 2.7% by weight (based on the weight of all solids of the mixture) at least one organic-based binder, acting as a solubilizer in the mixture, and c) 3 to 10% by weight (based on the weight of all solids of the mixtures) hydrous dispersing agent, and that the ceramic product contains less than 0.1% by weight (based on the total weight of the ceramic product) of carbon after the use thereof at temperatures above 600° C.

Abstract: According to typical inventive practice, precursor particulate is pressed and/or caste and/or molded and/or machined, thereby producing a porous green body of a desired shape. A gas is brought into contact with the porous green body so that, via reaction bonding between the gas and the porous green body, the porous green body becomes a porous reaction-bonded ceramic preform, geometrically corresponding to the porous green body. One or more infiltrant materials, at least one of which is glass or polymer, is/are caused to infiltrate the pores of the RB ceramic perform. The infiltrants are selected from glass, polymer, and metal. The infiltrated preform is permitted to cool and solidify, resulting in an embodiment of an inventive non-ceramic-infiltrated reaction-bonded-ceramic structure.

Abstract: A sintered material based on silicon carbide (SiC) reactively sintered between 1,100° C. and 1,700° C. to form a silicon nitride binder (Si3N4), intended in particular for fabricating an aluminum electrolysis cell, including 0.05% to 1.5% of boron, the Si3N4/SiC weight ratio being in the range 0.05 to 0.45.

Abstract: A sintered refractory block based on silicon carbide (SiC) with a silicon nitride (Si3N4) bond, for the manufacture of a aluminium electrolysis vessel, characterized in that it comprises, expressed in percentage by weight, at least 0.05% boron and/or between 0.05 and 1.2% calcium.

Abstract: A sintered cubic boron nitride (cBN) compact for use in a tool is obtained by sintering a mixture of (i) cubic boron nitride, (ii) aluminum oxide, (iii) one or more refractory metal compounds, and (iv) aluminum and/or one or more non-oxide aluminum compounds. The sintered bodies may have sufficient strength and toughness to be used as a tool material in solid, i.e. not carbide supported, form, and may be useful in heavy machining of cast irons.

Abstract: A sintered cubic boron nitride (cBN) compact for use in a tool is obtained by sintering a mixture of (i) cubic boron nitride, (ii) aluminum oxide, (iii) one or more refractory metal compounds, and (iv) aluminum and/or one or more non-oxide aluminum compounds. The sintered bodies may have sufficient strength and toughness to be used as a tool material in solid, i.e. not carbide supported, form, and may be useful in heavy machining of cast irons.

Abstract: A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium boride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

Abstract: A process for producing a silicon-containing CMC article that exhibits improved physical, mechanical, and microstructural properties at elevated temperatures exceeding the melting point of silicon. The process entails producing a body containing a ceramic reinforcement material in a solid matrix that comprises solid elemental silicon and/or silicon alloy and a ceramic matrix material. The ceramic matrix composite article is produced by at least partially removing the solid elemental silicon and/or silicon alloy from the solid matrix and optionally reacting at least part of the solid elemental silicon and/or silicon alloy in the solid matrix to form one or more refractory materials. The solid elemental silicon and/or silicon alloy is sufficiently removed from the body to enable the ceramic matrix composite article to structurally and chemically withstand temperatures above 1405° C.

Abstract: A sintered product of silicon nitride includes a crystal phase mainly having silicon nitride crystal grains and an amorphous grain-boundary phase located on the grain boundaries of the silicon nitride crystal grains. The grain-boundary phase contains lanthanum, aluminum, magnesium, silicon, and oxygen. The sintered product described above contains 0.1% by mass or more of lanthanum on an oxide basis, 0.05 to 0.6% by mass of aluminum on an oxide basis, 0.3% by mass or more of magnesium on an oxide basis, and 2.5% by mass or less of oxygen. The total amount of lanthanum on an oxide basis, aluminum on an oxide basis, and magnesium on an oxide basis is 3.5% by mass or less.

Abstract: A method of forming a nanoscale ceramic composite generally includes modifying a polymeric ceramic precursor, mixing the modified polymeric ceramic precursor with a block copolymer to form a mixture, forming an ordered structure from the mixture, wherein the modified polymeric ceramic precursor selectively associates with a specific type of block of the block copolymer, and heating the ordered structure for a time and at a temperature effective to form the nanoscale ceramic composite.

Abstract: A silicon nitride-melilite composite sintered body in accordance with the invention includes silicon nitride and a melilite Me2Si3O3N4, where Me denotes a metal element combining with silicon nitride to generate the melilite. The silicon nitride-melilite composite sintered body contains Si in a range of 41 to 83 mole percent in Si3N4 equivalent and Me in a range of 13 to 50 mole percent in oxide equivalent. The silicon nitride-melilite composite sintered body has an average thermal expansion coefficient that is arbitrarily adjustable in a range of 2 to 6 ppm/K at temperatures of 23 to 150° C. The silicon nitride-melilite composite sintered body has a high Young's modulus, a high mechanical strength, and excellent sintering performance. A device used for inspection of semiconductor in accordance with the invention utilizes such a silicon nitride-melilite composite sintered body.

Abstract: Highly wear-resistant, low-friction ceramic composites suited for machining-tool, sliding-component, and mold-die materials are made available. The ceramic composites characterized are constituted from a phase having carbon of 3 ?m or less, preferably 30 nm or less, average crystal-grain size as the principal component, and a ceramic phase (with the proviso that carbon is excluded). The ceramic phase is at least one selected from the group made up of nitrides, carbides, oxides, composite nitrides, composite carbides, composite oxides, carbonitrides, oxynitrides, oxycarbonitrides, and oxycarbides of Al, Si, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W. The ceramic composites are produced by sintering the source-material powders at a sintering temperature of 800 to 1500° C. and a sintering pressure of 200 MPa or greater.

Abstract: A silicon nitride sintered material includes a silicon nitride crystal and a grain boundary layer that contains at least two of a first metal silicide (a metal silicide having, as a first metal element, at least one selected from the group consisting of Fe, Cr, Mn and Cu), a second metal silicide (a metal silicide having, as a second metal element, at least one of W or Mo) and a third metal silicide (a metal silicide having a plurality of metal elements including the first metal element and the second metal element), wherein the grain boundary layer has neighboring phase where at least two of the first through third metal silicides exist in contact with each other.

Abstract: To provide a sintered silicon nitride with conductivity and densification, an oxide of titanium group elements, such as titanium oxide, hafnium oxide, zirconium oxide and the like, aluminum oxide and/or aluminum nitride is added as needed to silicon nitride-oxidant of rare-earth elements-aluminum oxide system or silicon nitride-oxide of rare-earth elements-magnesia system, and then specified quantity of carbon nonotube (CNT) is added to the above mixture. CNT generates silicon carbide after the reaction with contiguous or proximal silicon nitride and the like depending on the sintering duration at high temperature. Since silicon carbide is generated along with nanotubes, the silicon carbide functions as conductor with excellent heat resistance, corrosion resistance and the like.

Abstract: A member of supporting magnetic disc substrates is provided, comprising a ceramic sinter containing a ceramic component and at least one conductive component selected from a group consisting of iron, niobium, tin zinc, copper, nickel, cobalt, and chromium, wherein the ceramic sinter has conductive aggregates on its peripheral surface. In the member, the ceramic component may be forsterite and the conductive component is iron oxide, wherein the ceramic sinter comprises a main phase of 2MgO.SiO2 and a secondary phase of at least one of MgFe2O4, Fe3O4, and Fe2O3.

Abstract: A silicon nitride-bonded SiC refractory is provided, which includes SiC as a main phase and Si3N4 and/or Si2N2O as a secondary phase and which has a bending strength of 150 to 300 MPa and a bulk density of 2.6 to 2.9. A method for producing a silicon nitride-bonded SiC refractory is also provided, which comprises a step of mixing 30 to 70% by mass of a SiC powder of 30 to 300 ?m as an aggregate, 10 to 50% by mass of a SiC powder of 0.05 to 30 ?m, 10 to 30% by mass of a Si powder of 0.05 to 30 ?m, and 0.1 to 3% by mass, in terms of oxide, of at least one member selected from the group consisting of Al, Ca, Fe, Ti, Zr and Mg.

Abstract: A method of making a composite sintered silicon nitride/silicon carbide body, including mixing a predetermined amount of silicon nitride powder with a predetermined amount of silicon carbide powder, heat-treating the resultant mixed powder at a temperature of between about 800 and 1500 degrees Celsius in a substantially nitrogen sintering atmosphere, and producing a thin film of silica around individual silicon nitride and silicon carbide grains. The thin film of silica is useful in retarding the diffusion of oxygen to the silicon nitride particles, slowing their oxidation. The pressure of the sintering atmosphere is not substantially greater than atmospheric pressure.

Abstract: A method for producing sintered silicon nitride, including preparing a slurry from a base powder containing a silicon nitride powder and a sintering aid, the base powder having a particle size (D50) of 0.3 to 1 ?m; obtaining an SD powder from the slurry by a spray dryer process; and feeding the SD powder into a forming die and firing the powder under a compaction pressure of 3 ton/cm2 or more thereby obtaining sintered silicon nitride. The present invention provides a method for producing sintered silicon nitride with a higher degree of safety of the working environment.

Abstract: The present invention provides silicon nitride with tungsten carbide additives in a sinterable material comprising silicon nitride and tungsten carbide, in which the silicon nitride content is a minimum of about 80% and wherein the total nitride component is about 28-40 w/w % N2, and further comprising about 1.5-3.5 w/w % Al, about 2-6 w/w % Y, about 1.5-7 w/w % W, and about 3-9 w/w % O2. which after sintering will produce ceramic bodies with a high degree of toughness suitable for armor applications.

Abstract: A yttria sintered body is provided which includes yttria as a principal ingredient and 5 to 40 vol. % silicon nitride, and which exhibits enhanced corrosion resistance and mechanical strength.

Abstract: The present invention is directed to bearings produced from a silicon nitride material. The silicon nitride material consists of a sintering aid selected from the group consisting of Al2O3 and Y2O3, silicon dioxide, and optionally, up to 10 mole %, based on the amount of silicon nitride, of an additive that reacts with silicon nitride, said additive selected from the group consisting of TiO2, WO3, MoO3 and mixtures thereof.

Abstract: A high-strength machinable ceramic capable of high-precision fine machining has a coefficient of thermal expansion close to that of silicon and preferably a uniform blackish color which facilitates image processing of machined parts. The ceramic comprises a main constituent and a sintering aid. The main constituent comprises 30–59.95 mass % of boron nitride, 40–69.95 mass % of zirconia, optionally up to 20 mass % of silicon nitride and 0.05–2.5 mass % (calculated as an element) of at least one coloring additive, which is selected from C, Si, elements of Groups IIIA–IVB in the fourth period, elements of Groups IVA–VB in the fifth period, elements of Groups IVA–VIB in the sixth period of the long form periodic table, and compounds of these elements.

Abstract: A silicon nitride wear resistant member is composed of a ceramic sintered body containing 55 to 75 mass % of silicon nitride, 12 to 28 mass % of silicon carbide, 3 to 15 mass % of at least one element selected from the group consisting of Mo, W, Ta, and Nb in terms of silicide thereof, and 5 to 15 mass % of grain boundary phase composed of a rare earth element-Si—Al—O—N, the wear resistant member having an electrical resistance of 107 to 104 ?·cm, a porosity of 1% or less, and a three point bending strength of 900 MPa or more. The wear resistant member has a predetermined electric resistance (electro-conductivity) in addition to the high strength and toughness inherent in silicon nitride per se, especially has a high sliding characteristic. Also, a method of manufacturing the wear resistant member is provided.

Abstract: A conductive silicon nitride composite sintered body having an average grain size of 100 nm or less and whose relative roughness (Ra) after electric discharge machining is 0.3 ?m or less can be obtained by grinding/mixing a silicon nitride powder and a metal powder together until the average particle size of the silicon nitride powder becomes 30 nm or less, and subsequently by molding and sintering. It is preferable that the crushing/mixing is continued until it is apparent that a peak of added metal in an X-ray diffraction pattern has disappeared during the crushing/mixing.

Abstract: Composite materials containing silicon, titanium, carbon, and nitrogen, formed by spark plasma sintering of ceramic starting materials to a high relative density, demonstrate unusually high electrical conductivity as well as high-performance mechanical and chemical properties including hardness, fracture toughness, and corrosion resistance. This combination of electrical, mechanical, and chemical properties makes these composites useful as electrical conductors in applications where high-performance materials are needed due to exposure to extreme conditions such as high temperatures, mechanical stresses, and corrosive environments.

Abstract: The present invention consists of a synergistic mixture of Si3N4, Al2O3, AlN, SiO2 and Nd2O3. The cost effective synergistic composition is useful for the preparation of dense neodymium stabilised ?-Si3N4-?-SiAlON composite of the order of >98% theoretical density, having high hardness and high fracture toughness. The dense ?-Si3N4-?-SiAlON composite will be useful for low temperature applications as wear parts like bearing and roller materials and particularly for grinding and milling operations like grinding balls.

Abstract: A low-thermal-expansion, rigid and wear-resistant ceramic is provided. The low-thermal-expansion ceramic of the invention includes 60 vol % to 99.9 vol % of at least one selected from the group consisting of cordierite, spodumene and eucryptite and 0.1 vol % to 40 vol % of at least one selected from the group consisting of carbides, nitrides, borides and silicides of group IVa elements, group Va elements and group VIa elements, and boron carbide. The ceramic has a porosity of 0.5% or less and a thermal expansion coefficient, at 10° C. to 40° C., of 1.5×10?6/° C. or less.

Abstract: The present invention provides a process for the manufacture of dense neodymium stabilized ?-Si3N4-?-SiAlON composite, wherein a synergistic composition essentially consisting of Si3N4, Al2O3, AlN, SiO2 and Nd2O3 as starting materials is mixed in proportion to make a total of 100 mole in the mixed batch, passing the powder through 100 mesh, pressing the powder to form green compacts, sintering the green compacts at a temperature in the range of 1700° to 1900° C. in nitrogen atmosphere. The process of the present invention provides neodymium stabilized ?-Si3N4-?-SiAlON composites by processing a composition from the system Si3N4—Al2O3.AlN—Nd2O3.9AlN—SiO2 resulting into dense product of the order of >98% theoretical density with the advantages such as cost effectiveness, high hardness and high fracture toughness.

Abstract: The present invention provides a wear resistant member composed of silicon nitride sintered body containing 2–10 mass % of rare earth element in terms of oxide thereof as sintering agent, 2–7 mass % of MgAl2O4 spinel, 1–10 mass % of silicon carbide, and 5 mass % or less of at least one element selected from the group consisting of Ti, Zr, Hf, W, Mo, Ta, Nb and Cr in terms of oxide thereof, wherein a porosity of said silicon nitride sintered body is 1 vol. % or less, a three-point bending strength is 900 MPa or more, and a fracture toughness is 6.3 MPa·m1/2 or more. According to the above structure of the present invention, there can be provided a silicon nitride wear resistant member and a method of manufacturing the member having a high strength and a toughness property, and particularly excellent in rolling and sliding characteristics.

Abstract: A method of making nanoscale ordered composites of covalent ceramics through block copolymer-assisted assembly. At least one polymeric precursor is mixed with a block copolymer, and self-assembly of the mixture proceeds through an annealing process. During the annealing step, the polymeric precursor cross-links to form a structure robust enough to survive both the order-disorder transition temperature the block copolymer and the pyrolysis process, yielding ordered nanocomposites of high temperature ceramic materials. The method yields a variety of structures and morphologies. A ceramic material having at least one ceramic phase that has an ordered structure on a nanoscale and thermally stable up to a temperature of at least about 800° C. is also disclosed. The ceramic material is suitable for use in hot gas path assemblies, such as turbine assemblies, boilers, combustors, and the like.

Abstract: The present invention provides a silicon nitride-based sintered body having excellent mechanical properties from room temperature to a medium-low temperature range, a low friction coefficient and excellent wear resistance; a raw material powder for the sintered body; a method of producing the raw material powder; and a method of producing the sintered body. The sintered body of the present invention comprises silicon nitride, titanium compounds and boron nitride, or else silicon nitride, a titanium-based nitride and/or carbide, silicon carbide and graphite and/or carbon; and it has a mean particle diameter of 100 nm or less, and a friction coefficient under lubricant-free conditions of 0.3 or less, or else 0.2 or less.

Abstract: Sintered silicon nitride products comprising predominantly ?-silicon nitride grains in combination with from about 0.1 to 30 mole % silicon carbide, and grain boundary secondary phases of scandium oxide and scandium disilicate. Such products have high fracture toughness, resistance to recession, and resistance to oxidation at temperatures of at least 1500° C. Methods for preparing sintered silicon nitride products are also disclosed.

Abstract: The invention relates to a silicone nitride based substrate for semi-conductor components, said substrate containing silicon nitride (Si3N4), silicon carbide (SIC) and silicon oxynitride(Si2N2O) as crystalline phases. The silicon phase content is less or equal to 5%, the shrinkage during production is less than 5% and the open porosity of the substrate is less than 15% vol. %. The invention also relates to a method for the production and use of said substrate as an element of semi-conductor components, particularly thin film solar cells, and semi-conductor components which contain said substrate.

Abstract: A silicon nitride sintered material containing a silicon nitride component and silicon carbide having an average particle size of 1 ?m or less in an amount of at least 1 mass % and less than 4 mass %, based on 100 mass % of the silicon nitride component. The carbide is dispersed in the silicon nitride component, and the silicon nitride sintered material has a thermal expansion coefficient of at least 3.7 ppm/° C. between room temperature and 1,000° C. The silicon nitride component contains a rare earth element in an amount of 15-25 mass % as reduced to a certain oxide thereof and Cr in an amount of 5-10 mass % as reduced to a certain oxide thereof, and a crystalline phase is present in intergrain regions of the sintered material.

Abstract: The present invention provides a silicon nitride based sintered body having excellent mechanical properties from room temperature to a medium low temperature range, a low friction coefficient and excellent wear resistance. The sintered body comprises silicon nitride, titanium compounds and boron nitride or silicon nitride, titanium based nitride and/or carbide, silicon carbide and graphite and/or carbon; and has a mean particle diameter of 100 nm or less and a friction coefficient under lubricant free conditions of 0.3 or less.

Abstract: Fiber-reinforced ceramic composites contain bundles, tows or hanks of long fibers, wherein the long fiber bundles, tows or hanks are completely surrounded by a short fiber-reinforced matrix, with the long and short fibers having, independently of one another, a mean diameter of from 4 to 12 &mgr;m and the long fibers having a mean length of at least 50 mm and the short fibers having a mean length of not more than 40 mm, a process for producing them and their use for producing clutch disks or brake disks.

Abstract: The object of the present invention is to provide a ceramic body that can support a required amount of a catalyst component, without lowering the characteristics such as strength, being manufactured without forming a coating layer and providing a high performance ceramic catalyst that is excellent in practical utility and durability. A noble metal catalyst is supported directly on the surface of the ceramic body and the second component, consisting of compound or composite compound of element having d or f orbit in the electron orbits thereof such as W, Co, Ti, Fe, Ga and Nb, is dispersed in the first component made of cordierite or the like that constitutes the substrate ceramic. The noble metal catalyst can be directly supported by bonding strength generated by sharing the d or f orbits of the second component, or through interaction with the dangling bond that is generated in the interface between the first component and the second component.

Abstract: Wear resistant member comprises a silicon nitride sintered body. Silicon nitride sintered body contains from 75 to 97% by mass of silicon nitride, from 0.2 to 5% by mass of titanium nitride and from 2 to 20% by mass of a grain boundary phase essentially containing Si—R—Al—O—N compound (R: rare earth element). Particles of titanium nitride are 1 &mgr;m or less in long axis. Particles of titanium nitride are mainly spherical particles of which aspect ratio is in the range of from 1.0 to 1.2, surface thereof being formed edgeless and roundish. Wear resistant member formed of such silicon nitride sintered body is excellent in strength, fracture toughness and rolling fatigue life. In particular, being excellent in rolling fatigue life, it is suitable for bearing member such as bearing balls.

Abstract: The present invention relates to a silicon carbide-boron nitride composite material, which synthesised according to an in-situ chemical reaction between silicon nitride, boron carbide and carbon, and which contains fine boron nitride particles dispersed in a silicon carbide matrix, wherein aforementioned composite material is obtained by molding a powder mixture containing each of the components required in the in-situ reaction and sintering the mixture.