Preparation of Silicon Carbide Ceramics with Self-reinforced Microstructure by the Control of Starting Phases

,; ,; ,; ,; ,; ,; ,; ,

J. Korean Ceram. Soc. > Volume 34(12); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(12): 1240.

출발상 제어에 의한 자기복합화 미세구조의 탄화규소 세라믹스 제조

이종국, 강현희, 이은구, 김환¹

조선대학교 재료공학과
¹서울대학교 무기재료공학과

Preparation of Silicon Carbide Ceramics with Self-reinforced Microstructure by the Control of Starting Phases

ABSTRACT

Silicon carbides with self-reinforced microstructure which hore a small grain matrix and dispersed large grains with rod-like type were prepared by the liquid-phase sintering and the control of starting phases of raw materials. The specimens with self-reinforced microstructure could be obtained from the compacts with mixed compositions of $alpha$-SiC and 10-50 % $beta$-SiC powders and by the pressureless sintering at 185$0^{circ}C$ for 5h. Large grains with rod or plate-like types were 4H-SiC and small grains with equi-axed type were 6H-SiC. Fracture grains with rod or plate-like types were 4h-SiC and small grains with equi-axed type were 6H-SiC. Fracture toughness of specimens with self-reinforced microstructure was increased by the crack deflection and formation of microcracking due to the existence of rod-like large grains during crack propagation.

Key words: Silicon carbides, Self-reinforced Microstructure, Liquid-phase sintering