Bayer Aktiengesellschaft

Bayer Aktiensesellschaft

Ernst Gugel

Bernhard Freudenberg

Johannes Seyer

Peter Woditsch

Gerhard Leimer

Hans Andreas Lindner

Gerhard W&ouml;tting

Isfried Petzenhauser

A sintered Si N material, valves and components made with the material, and methods for making same.

Sintered silicon nitride, components made therewith, specially valves, methods for the production and use thereof

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.

Process for production of a Si.sub.3 N.sub.4, based material

Ceramics having principal phases of aluminum iron titanate and mullite corresponding to the overall chemical composition:

Ceramics based on aluminum titanate, process for their production and

Sintered ceramic material which comprises doped aluminum titanate and mullite having the composition:

Sintered ceramic materials based on aluminium titanate, a process for

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.

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Roedental, Germany

Ernst Gugel