A ceramic matrix composite includes a substrate which contains a fibrous body made of silicon carbide fiber, and a matrix which is formed in the substrate, and which contains silicon carbide and a silicon material made of silicon or a binary silicon alloy.

A process of manufacturing a chromium alloyed molybdenum silicide portion of a heating element comprising the steps of: forming a mixture of a chromium powder and a silicon powder; reacting the mixture to a reaction product in an inert atmosphere at a temperature of at least 1100? C. but not more than 1580? C.; converting the reaction product to a powder comprising CrSi.sub.2; forming a powder ceramic composition by mixing the powder comprising CrSi.sub.2 with a MoSi.sub.2 powder and optionally with an extrusion aid; forming the portion of the heating element; and sintering the portion of the heating element in a temperature of from about 1450? C. to about 1700? C.; characterized in that the chromium powder and the silicon powder are provided separately to the mixture.

Disclosed are a silicon nitride ceramic sintered body and preparation method thereof. The silicon nitride ceramic sintered body includes a sintered bulk and a hard surface layer having a thickness of 10-1000 m, formed on a surface of the sintered bulk, wherein the sintered bulk comprises a first silicon nitride crystalline phase and a first grain boundary phase; the hard surface layer comprises a second silicon nitride crystalline phase and a second grain boundary phase; the first grain boundary phase comprises a metal tungsten phase being tungsten elementary substance and/or a tungsten alloy; the second grain boundary phase comprises tungsten carbide particles; tungsten element in the metal tungsten phase accounts for 80-100 wt % of total tungsten element in the first grain boundary phase; and tungsten element in the tungsten carbide particles accounts for 60-100 wt % of total tungsten element in the second grain boundary phase.

A silicon carbide porous body contains -SiC particles, Si particles, and metal silicide particles. The maximum particle diameter of the -SIC particles is not smaller than 15 m. The content of the Si particles is not lower than 10 mass %. The maximum particle diameter of the Si particles is not larger than 40 m. Further, an oxide coating film having a thickness not smaller than 0.01 m and not larger than 5 m is provided on surfaces of the Si particles.

Disclosed are a silicon nitride ceramic sintered body and a-preparation method thereof. The silicon nitride ceramic sintered body includes a sintered bulk and a hard surface layer having a thickness of 10-1000 m, formed on a surface of the sintered bulk, wherein the sintered bulk comprises a first silicon nitride crystalline phase and a first grain boundary phase; the hard surface layer comprises a second silicon nitride crystalline phase and a second grain boundary phase; the first grain boundary phase comprises a metal tungsten phase being tungsten elementary substance and/or a tungsten alloy; the second grain boundary phase comprises tungsten carbide particles; tungsten element in the metal tungsten phase accounts for 80-100 wt % of total tungsten element in the first grain boundary phase; and tungsten element in the tungsten carbide particles accounts for 60-100 wt % of total tungsten element in the second grain boundary phase.

A complex composite particle is made of a coal dust and binder composite that is pyrolyzed. Constituent portions of the composite react together causing the particles to increase in density and reduce in size during pyrolyzation, yielding a particle suitable for use as a proppant or in a composite structure.

A composite material and a method of using the composite material. The composite material consists of at least 65 volume percent cubic boron nitride (cBN) grains dispersed in a binder matrix, the binder matrix comprising a plurality of microstructures bonded to the cBN grains and a plurality of intermediate regions between the cBN grains; the microstructures comprising nitride or boron compound of a metal; and the intermediate regions including a silicide phase containing the metal chemically bonded with silicon; in which the content of the silicide phase is 2 to 6 weight percent of the composite material, and in which the cBN grains have a mean size of 0.2 to 20 m.

It is difficult for a CrSi-based sintered body composed of chromium silicide (CrSi.sub.2) and silicon (Si) to have high strength. Provided is a CrSi-based sintered body including Cr (chromium) and silicon (Si), in which the crystal structure attributed by X-ray diffraction is composed of chromium silicide (CrSi.sub.2) and silicon (Si), a CrSi.sub.2 phase is present at 60 wt % or more in a bulk, a density of the sintered body is 95% or more, and an average grain size of the CrSi.sub.2 phase is 60 ?m or less.

A method for manufacturing a turbomachine blade made of ceramic matrix composite component includes at least a structural part and a functional part secured to the structural part, the method including obtaining an assembly including a first preform of the functional part that is mounted on a second preform of the structural part or on the structural part, the first preform including a fibrous reinforcement of short fibres, and the second preform or the structural part comprising a woven fibrous reinforcement, and densification of the first preform of the assembly by infiltration with a molten composition.

A method for manufacturing a magnesium-based thermoelectric conversion material of the present invention includes a raw material-forming step of forming a raw material for sintering by adding silicon oxide in an amount within a range equal to or greater than 0.5 mol % and equal to or smaller than 13.0 mol % to a magnesium-based compound, and a sintering step of heating the raw material for sintering at a temperature within a range equal to or higher than 750 C. and equal to or lower than 950 C. while applying pressure equal to or higher than 10 MPa to the raw material for sintering so as to form a sintered substance.