Process for production of a Si.sub.3 N.sub.4, based material
AssigneeBayer Aktiengesellschaft
InventorsGerhard Leimer, Gerhard Wotting, Ernst Gugel
Life of this patent
Estimating the term…
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.
Claims10
A process for the production of high-strength Si.sub.3 N.sub.4 -based material with a narrow range spread of values for mechanical properties which comprises:
- molding a powder-form starting mixture consisting essentially of 5 to 20% by weight finely divided elemental silicon, 1 to 15% by weight of at least one sintering additive and 65-94% by weight powdered Si.sub.3 N.sub.4, heat treating the starting mixture at a temperature equal to or below 1400.degree. C. in a nitrogen atmosphere at atmospheric pressure until a complete reaction of the elemental silicon with the nitrogen gas to Si.sub.3 N.sub.4 takes place, and continuing the heat treating of the mixture after all of the elemental silicon has been converted to Si.sub.3 N.sub.4, at a temperature above 1400.degree. C., to obtain a sintered molding very near the theoretical density of the material.
A process for the production of high-strength Si.sub.3 N.sub.4 -based material with a narrow range spread of values for mechanical properties which comprises:
- molding a powder-form starting mixture consisting essentially of 5 to 10% by weight finely divided elemental silicon, 1 to 15% by weight of at least one sintering additive and 75-94% by weight powdered Si.sub.3 N.sub.4, heat treating the starting mixture at a temperature equal to or below 1400.degree. C. in a nitrogen atmosphere until a complete reaction of the elemental silicon with the nitrogen gas to Si.sub.3 N.sub.4 takes place, and continuing the heat treating of the mixture after all of the elemental silicon has been converted to Si.sub.3 N.sub.4, at a temperature above 1400.degree. C., to obtain a sintered molding very near the theoretical density of the material.
Dependencies are inferred from the claim text.