Mitsubishi Materials Corporation

Other

Mitsubishi Mining and Cement Co. Ltd.

Hisao Ueda

Hiroshi Sasaki

Koichi Niihara

Ryuichi Matsuki

Takeyoshi Takenouchi

The ceramic composites consisting of sintered alumina comprising a polycrystalline alumina matrix having a grain size of from 0.5 to 10 .mu.m, and fine particles of TiB.sub.2 2 .mu.m or less in diameter being dispersed in the alumina grains, the composite alumina ceramic containing from 15 to 40% by volume of TiB.sub.2 ; or a ceramic composites comprising a polycrystalline alumina matrix as above, fine particles of TiB.sub.2, and fine particles of SiC, the fine particles of TiB.sub.2 and SiC being each 2 .mu.m or less in diameter and being dispersed in the alumina grains, the ceramic composites containing from 5 to 30% by volume of TiB.sub.2 and from 5 to 30% by volume of SiC.

Ceramic composites and process for manufacturing the same

A ceramics composites prepared by dispersing any one of the following materials (i) to (viii) in Al.sub.2 O.sub.3 which as a matrix-containing crystalline grains having a grain size of 0.5 to 100 .mu.m. (i) 3 to 40% by volume of fine TiN particles having a particle size of not more than 2 .mu.m and 3 to 40% by volume of fine SiC particles having a particle size of not more than 2 .mu.m. (ii) 3 to 40% by volume of fine TiN particles having a particle size of not more than 2 .mu.m and 3 to 40% by volume of fine Si.sub.3 N.sub.4 particles having a particle size of not more than 2 .mu.m. (iii) 2 to 35% by volume of fine TiC particles having a particle size of not more than 2 .mu.m and 5 to 40% by volume of SiC whiskers having a diameter of 0.05 to 2 .mu.m. (iv) 2 to 35% by volume of fine TiC particles having a particle size of not more than 2 .mu.m and 5 to 40% by volume of Si.sub.3 N.sub.4 whiskers having a diameter of 0.1 to 2 .mu.m. (v) 3 to 40% by volume of fine TiN particles having a particle size of not more than 2 .mu.m and 3 to 30% by volume of SiC whiskers having a diameter of 0.05 to 2 .mu.m. (vi) 3 to 40% by volume of fine TiN particles having a particle size of not more than 2 .mu.m and 3 to 30% by volume of Si.sub.3 N.sub.4 whiskers having a diameter of 0.1 to 2 .mu.m. (vii) 2 to 35% by volume of fine TiC particles having a particle size of not more than 2 .mu.m and 5 to 40% by volume of fine SiC particles having a particle size of not more than 2 .mu.m. (viii) 2 to 35% by volume of fine TiC particles having a particle size of not more than 2 .mu.m and 5 to 40% by volume of fine Si.sub.3 N.sub.4 particles having a particle size of not more than 2 .mu.m.

Ceramic composites and process for its production

A MgO/SiC composite material in which SiC particles with nano-meter order in size are dispersed within MgO matrix grains can be prepared by hot-pressing the mixture of fine MgO and SiC powders. Addition of SiC particles in the range of 5 volume percent to 50 volume percent to the MgO matrix increased remarkably the fracture strength and the hardness in a nanometer-order structure of the composite.

Growing community of inventors

Saitama, Japan

Hisao Ueda