Abstract: The present invention provides a composite pressure-sintered material comprising a continuous phase of hexagonal boron nitride and, dispersed therein, a second material comprising (a) at least one metal nitride selected from the group consisting of silicon, aluminium and titanium nitrides and (b) at least one stable metal oxide; wherein the amount of metal oxide is such that the second material does not contain more than 35% by weight of oxygen. This material possesses a low thermal expansion coefficient and therefore reveals good thermal shock resistance. Another characteristic of this material is its low wettability by molten steel which is thus responsible for excellent chemical resistance to liquid metal. Finally, this material is exceptionally mechanical wear resistant.

Abstract: The invention comprises a self-lubricating ceramic composite characterized as having a low porosity derived from a mixture of at least one ceramic powder preferably selected from the group consisting of silicon nitride, silicon carbide, zirconia, alumina, zirconium nitride, tungsten carbide, and titanium carbide; a cemetitious binder, effective amounts of at least one metal silicide, and at least one metal oxide. The ceramic powder mixture can be slurried with sufficient amounts of water and subsequently subjected to pressures of about 6.0 to 7.0 MPa in a mold at temperatures of about 125° to 175° C. to form a self-lubricating ceramic composite capable of maintaining hot-hardness temperatures above 750° C. These self-lubricating ceramic composites are particularly useful in the manufacture of high-performance turbine engines, including engine parts, bearings, gears, rotors and in other areas where high-heat lubricating properties of the ceramic composite are required.

Abstract: Wear resistant member for electronic equipment comprises a silicon nitride sintered body that contains conductivity enhancing particles, and has electrical resistivity in the range from 1 to 105 &OHgr;·m. In silicon nitride sintered body, agglomeration of conductivity enhancing particles in which distance between conductivity enhancing particles is less than 1 &mgr;m exists by 30% or less by area ratio per unit area. Wear resistant member is used for a bearing ball or the like, being applied in a rotation actuator of electronic equipment such as a magnetic recorder and optical disk drive. Malfunction of electronic equipment due to static electricity may be cancelled due to electrical resistivity that silicon nitride sintered body has.

Abstract: The present invention provides a cubic boron nitride-based sintered material excellent in durability and usable for a cutting tool material capable of carrying out high speed cutting of at least a high grade cast iron represented with a Ni-Resist cast iron and an austempered cast iron and having a long life. The present invention further provides a method for manufacturing the cubic boron nitride-based sintered material. The method for the production of a cubic boron nitride-based sintered material includes preparing a starting mixture by mixing particles of cubic boron nitride with a binding powders based on the system of TiCN, Si3N4, Al2O3, and CrxN, wherein x varyies from 1 to 2.7; and subjecting the starting mixture to a sintering process under pressure and at the same time at a high temperature; and recovering a sintered product.

Abstract: A silicon nitride-tungsten carbide composite sintered material which contains silicon nitride and tungsten carbide, and characterized in that in an arbitrary cross-section of the sintered material, the ratio of the area of a tungsten carbide portion to that of the entirety of the cross-section is 20-35%, and a tungsten carbide aggregation portion having a longitudinal length of at least 5 &mgr;m is present in the arbitrary cross-section. The production process includes firing raw material powder containing tungsten carbide powder and two silicon nitride powders having different particle sizes.

Abstract: A silicon nitride sintered material includes a polycrystal material having silicon nitride crystal grains and a grain boundary phase. The sintered material contains a Yb element in an amount of 2 to 30% by weight in terms of its oxide and an Al element in an amount of 1 to 20% by weight in terms of its oxide and has a thermal conductivity of 40 W/mK or less at room temperature, a resistivity of 1×105 to 1×1012 &OHgr;·cm at room temperature, and a porosity of 0.5% or less.

Abstract: A sensor material for measuring physical parameters capable of configuring a sensor capable of directly measuring a high value of physical parameters such as high stress or high pressure without employing a pressure resistance container. The sensor material for measuring static and dynamic physical parameters includes a matrix made of an electrically insulating ceramic material, and piezoresistance materials which are dispersed in the matrix so as to be electrically continuous to each other.

Abstract: The present invention relates to a titanium diboride sintered body and a method for manufacturing thereof wherein silicon nitride is added to a titanium diboride as a sintering aid. The sintered body according to the present invention has a fine structure and excellent physical characteristics such as a strength, hardness, etc. Therefore, the sintered body according to the present invention may be applicable to certain materials which requires high strength and hardness.

Abstract: A composite material has a quartz glass phase and a complex compound phase compounded with the quartz glass phase, which is made of one or more compounds selected from a group of silicon carbide, silicon nitride, silicon, titanium nitride and titanium carbide, as a main ingredient. The composite material can be used instead of quartz glass, and can prevent the generations of microcrack, tipping and particles after the mechanical working.

Abstract: Cubic boron nitride composite particles containing hard microparticles dispersed in cubic boron nitride particles. The hard microparticles have an average particle size of about 10 nm to about 10 &mgr;m and a particle size equal to or smaller than one-third of the particle size of any of the cubic boron nitride particles, and the amount of the hard microparticles dispersed in the cubic boron nitride particles is from about 1% to about 50% by volume.

Abstract: A silicon nitride—tungsten carbide composite sintered and process for preparing the same which contains silicon nitride and tungsten carbide, and is characterized in that the total in amounts of an entirety of rare earth elements as reduced to certain corresponding oxides thereof, the elements being contained in the sintered material, and excess oxygen as reduced to silicon dioxide is 6-20 mass %; the ratio, on a mol basis, of (the amounts of rare earth elements as reduced to the certain corresponding oxides thereof)/(the amounts of the rare earth elements as reduced to the corresponding oxides thereof+the amount of excess oxygen as reduced to silicon dioxide) is 0.3-0.7; a crystalline phase is present in an intergrain region of the sintered material; and an effective firing temperature range within which a flexural strength of at least 800 MPa is obtained encompasses at least 100 degrees.

Abstract: The present invention relates to a titanium diboride sintered body and a method for manufacturing thereof wherein silicon nitride is added to a titanium diboride as a sintering aid. The sintered body according to the present invention has a fine structure and excellent physical characteristics such as a strength, hardness, etc. Therefore, the sintered body according to the present invention may be applicable to certain materials which requires high strength and hardness.

Abstract: A MoSi2 pest resistant material includes in-situ grown &bgr;-Si3N4 whiskers. In addition to excellent pest resistance, the material provides a lower coefficient of thermal expansion for better match with continuous reinforcing fibers such as SiC fibers. A two stage heating and pressing production technique enables lower temperature processing with substantially full densification.

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: A composition and method of fabricating pressureless sintered 70 volume % silicon nitride—30 volume % barium aluminum silicate ceramic composites. The composites are made from 70 volume % silicon nitride, containing varying amounts and size distributions of initial &bgr;-silicon nitride, and 30 volume % barium aluminum silicate. The resulting ceramic composites contain microstructures with coarse &bgr;-silicon nitride whiskers, as well as narrow distributions of short &bgr;-silicon nitride whiskers, surrounded by fine barium aluminum silicate grains. The resulting composites exhibit improved fracture toughness and flexural strength.

Abstract: There is disclosed a silicon nitride sintered body produced by sintering a molded article which comprises a mixture of a silicon nitride powder as the main component and plural kinds of sintering additives, wherein said silicon nitride powder is set to be 0.1 to 1.0 &mgr;m in average grain size, and said plural kinds of sintering additives includes first and second sintering additives, said first sintering additive comprising oxide powders of at least one element of Group 3a element, said second sintering additive comprising oxide powders of at least one element selected from Zr (zirconium), Hf (hafnium), Nb (niobium), Ta (tantalum) and W (tungsten), said first sintering additive having the average grain size set to be 0.1 to 10 times as large as the average grain size of said silicon nitride powder and being incorporated in an amount ranging from 0.

Abstract: A composition and method of fabricating pressureless sintered 70 volume % silicon nitride-30 volume % barium aluminum silicate ceramic composites. The composites are made from 70 volume % silicon nitride, containing varying amounts and size distributions of initial &bgr;-silicon nitride, and 30 volume % barium aluminum silicate. The resulting ceramic composites contain microstructures with coarse &bgr;-silicon nitride whiskers, as well as narrow distributions of short &bgr;-silicon nitride whiskers, surrounded by fine barium aluminum silicate grains. The resulting composites exhibit improved fracture toughness and flexural strength.