Abstract: A process for producing polycarbosilane partly containing siloxane bonds, ich comprises adding 0.01 to 15% by weight of polyborosiloxane having phenyl groups in at least a part of the side chains of Si with its skeletal structure being composed of B, Si and O to a polysilane having the structure ##STR1## wherein n is at least 3, and R.sub.1 and R.sub.2, independently from each other, represent methyl, ethyl, phenyl or hydrogen; and heating the polymer mixture in an atmosphere inert to the reaction thereby to polymerize it. The polycarbosilane has excellent properties, and is especially suitable as a raw material for the production of silicon carbide fibers.

Abstract: Metal nitride sintered moldings are produced by mixing metal nitride powders with an organosilicon compound or an organosilicon high molecular weight compound as a binder, molding the mixture into a desired shape and heating the formed molding under a non-oxidizing atmosphere to sinter the metal nitride powders.

Abstract: Organosilicon high molecular weight compounds containing silicon and carbon as the main skeleton components and organosilicon high molecular weight compounds containing silicon and carbon as the main skeleton components and 0.01-20% by weight of at least one foreign element other than silicon, carbon, hydrogen and oxygen have a number average molecular weight of 500-30,000, and intrinsic viscosity of 0.01-1.50 and a silicon carbide residual amount of not less than 40% by weight after baked at a temperature of 800.degree.-1,500.degree. C. in a non-oxidizing atmosphere and are useful for the production of silicon carbide moldings.

Abstract: A heat-resistant composite material reinforced with continuous silicon carbide fibers is produced by forming a powdery ceramics matrix and the fibers into a composite, and pressing and heating the composite into a sintered composite. The composite material is excellent in the mechanical strength at a high temperature, heat resistance, oxidation resistance and corrosion resistance.

Abstract: Novel borosiloxane polymers are produced by heating at least one of a boric cid compound with phenylsilane to effect polycondensation reaction.

Abstract: Cobalt or cobalt alloy composite materials reinforced with continuous silicon carbide fibers, which have a high tensile strength, a low elongation, a high Young modulus and a high tensile strength at a high temperature, are produced by filling spaces in piles of the continuous silicon carbide fibers containing 0.01%-30% by weight of free carbon with melted or powdery metallic cobalt or cobalt alloy and integrating the said fibers with the said metal.

Abstract: Beryllium composite material reinforced with continuous silicon carbide fibers is obtained by bonding tightly continuous silicon carbide fibers obtained by baking spun fibers of organosilicon high molecular weight compound, with beryllium and its alloys as a matrix. The silicon carbide fiber-beryllium composite material is excellent in the mechanical strength, heat resistance and oxidation resistance, and is useful as a material for aerospace instrument and a material for nuclear industry.

Abstract: Light metal composite materials reinforced with novel continuous silicon carbide fibers composed of aluminum, aluminum alloy or magnesium alloy matrix and the continuous silicon carbide fibers containing 0.01-40% by weight of free carbon, in which the free carbon is reacted with aluminum or added metal elements in the aluminum alloy or magnesium alloy to form carbides. When the silicon carbide fibers are coated with a metal or ceramics, the wettability of the silicon carbide fibers to said matrix is more improved.

Abstract: Heat resistant and super hard composite materials are produced by mixing more than 60% by weight of an organosilicon high molecular weight compound, the main skeleton components of which are silicon and carbon or an organosilicon high molecular weight compound, the main skeleton components of which are silicon and carbon and which contains foreign elements other than silicon, carbon, hydrogen and oxygen with not less than 40% by weight of metal material powders consisting mainly of at least one metal element, molding the mixture into a shaped article and baking the shaped article under a non-oxidizing atmosphere at a temperature of lower than the semi-melting point of the above described metal powders.

Abstract: A hydrogen-occluding alloy consisting of at least one element selected from rare-earth elements R and magnesium or of at least one element selected from rare-earth elements R, magnesium and nickel has a small density and is inexpensive and has an excellent hydrogen occlusion capacity as compared with the conventional La-Ni series alloys. The R-Mg series alloys and R-Ni-Mg series alloys are suitable as a material for hydrogen container.

Abstract: Silicon carbide sintered moldings having a high strength and a high oxidation resistance at high temperatures are produced by mixing SiC matrix powders with a binder consisting of an organosilicon high molecular weight compound having silicon and carbon as the main skeleton components and containing at least one foreign element other than silicon, carbon, hydrogen and oxygen, molding the mixture into the desired shape and baking the formed molding at high temperatures.

Abstract: Silicon carbide sintered moldings having a high flexural strength and various excellent properties are produced by mixing SiC powders or SiC fibers with a binder or organosilicon low molecular weight compounds or organosilicon high molecular weight compounds, molding the mixture into a desired shape and heating the molded mixture at a high temperature.

Abstract: Silicon carbide sintered moldings having a high flexural strength and various excellent properties are produced by mixing SiC powders with a binder of organosilicon low molecular weight compounds or organosilicon high molecular weight compounds, molding the mixture into a desired shape, heating the molding at a high temperature to form SiC sintered molding, impregnating the SiC sintered molding with the above described organosilicon compound and heating the impregnated SiC sintered molding, if necessary, said impregnation and heat treatment being repeated two or more times.

Abstract: Silicon carbide fibers having a high tensile strength are produced by(1) dissolving at least one of organosilicon high molecular weight compounds having a softening point of higher than 50.degree. C, in which silicon and carbon are the main skeleton components, in a solvent for the organosilicon high molecular weight compounds or heating and melting said organosilicon high molecular weight compounds to prepare a spinning solution and spinning said spinning solution into filaments,(2) preliminarily heating the spun filaments at a temperature of 350.degree.-800.degree. C under vacuum to volatilize low molecular weight compounds contained in the high molecular weight compounds, and(3) baking the thus treated filaments at a temperature of 800.degree.-2,000.degree. C under vacuum or at least one non-oxidizing atmosphere selected from the group consisting of an inert gas, CO gas and hydrogen gas, to form silicon carbide fibers.

Abstract: Organosilicon high molecular weight compounds having silicon and carbon as the main skeleton components and consisting of a mixture of linear polycarbosilanes having silicon and carbon as the main skeleton components, cyclic polycarbosilanes having silicon and carbon as the main skeleton components and polycarbosilanes in which linear carbosilane and cyclic carbosilane are chemically bonded are produced by thermally decomposing and polycondensing at least one of organosilicon compound having polysilane skeleton selected from the group consisting of cyclic polysilanes shown by the following formula(R.sub.1.R.sub.2.Si)n, n.gtoreq.4wherein R.sub.1 and R.sub.2 are hydrogen, alkyl group, aryl group, silyl group, or a halogen and linear polysilane shown by the following formula ##STR1## WHEREIN R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are hydrogen, alkyl group, aryl group, silyl group or a hologen, by heating at a temperature of 300.degree.-2,000.degree.