Abstract: A sintered Si3N4 material, valves and components made with the material, and methods for making same.

Abstract: A sintered Si3N4 material, valves and components made with the material, and methods for making same.

Abstract: High-strength Si.sub.3 N.sub.4 -based material with a narrow range spread of values for mechanical properties useful for producing thick-walled ceramic parts for internal combustion engines, thick-walled ceramic fittings or cutting tools is produced by molding a powder-form starting mixture comprising powdered Si.sub.3 N.sub.4, finely divided elemental silicon and sintering additives, and subsequently heat treating the mixture to obtain a sintered molding very near the theoretical density of the material.

Abstract: Ceramics having principal phases of aluminum iron titanate and mullite corresponding to the overall chemical composition:50 to 62% by weight Al.sub.2 O.sub.3,36 to 49.5% by weight titanium oxide, expressed as TiO.sub.2,0.5 to 10% by weight SiO.sub.2, and0.2 to 15% by weight iron oxide, expressed as Fe.sub.2 O.sub.3,up to 1% by weight impurities,with the sum of Al.sub.2 O.sub.3, TiO.sub.2 and SiO.sub.2 being 100%,wherein the sum of the crystalline phases Al.sub.2 O.sub.3, TiO.sub.2, SiO.sub.2 (other than the principal phases) is less than 6% by weight, based on the sintered body, are useful where a ceramic having a high thermal-shock-resistance is required, such as exhaust port liner internal combustion engines, for example.

Abstract: Sintered ceramic material which comprises doped aluminum titanate and mullite having the composition:50-61.5% by weight Al.sub.2 O.sub.3,36-47.5% by weight titanium oxide, expressed as TiO.sub.2,2.5-5% by weight SiO.sub.2,with the sum total of the three components adding up to 100%, and which further comprises 0.3 to 1% by weight MgO and up to 1% by weight impurities, useful as, inter alia, filters, catalyst supports and internal combustion engine parts, are prepared by mixing and shaping materials of suitable composition and then sintering the shaped composition at temperatures of 1250.degree. to 1600.degree. C. over a holding time of 0.5 to 100 hours.

Abstract: Zirconyl phosphate ceramics having high strength and high heat shock resistance, which consist essentially of at least 99% by weight of zirconyl phosphate, zirconium phosphates or both and no other phase material in quantities of more than 1% by weight are useful in ceramic filters and ceramic internal combustion engine parts and are prepared by mixing zirconyl phosphate or substances which form zirconyl phosphate with an antimony compound, moulding the resulting mixture and then sintering the moulded mixture at temperatures of 1200.degree. to 1700.degree. C.

Abstract: Method for the production of a polycrystalline shaped body of silicon carbide of a density of at least 98% of the theoretical density of silicon carbide, prepared through pressureless sintering at temperatures from 1,900 to 2,200 C. from at least 97 weight % of .alpha.-silicon carbide and/or .beta.-silicon carbide under addition of up to 3 weight % of boron, characterized by the fact that the shaped body is prepared without any carbon additions to the batch and is pressureless sintered in a carbon containing protective gas atmosphere.

Abstract: Polycrystalline shaped body of a density of at least 98% of the theoretical density of silicon carbide, consisting of at least 92 weight % of .alpha.-silicon carbide and/or .beta.-silicon carbide, which is present in the form of a homogeneous texture with grains of maximal 10 .mu.m, and is characterized by the fact that, besides a content of up to 3 weight % of boron, a share of about 0.5 to 5 weight % of a metal or rare earth element that acts reducing or mixtures thereof is present, and the body shows a transverse rupture strength (determined by the four-point method) of at least 500 N/mm.sup.2 up to 1,400 C and is essentially free of free carbon.A method for the production of shaped bodies through the pressureless sintering of the silicon carbide starting material, characterized by the fact that about 0.