초미립 SiC가 첨가된 질화규소에서 미세구조에 미치는 Bedding의 영향

Abstract

The effect of bedding on the microstructure of Si3N4 added with ultra-fine SiC was investigated. The bedding and the addition of ultra-fine SiC effectively inhibited grain growth of Si3N4 matrix grain. The microstructures of the specimens sintered with bedding powder consisted of fine-grains as compared with the specimens sintered without bedding powder. In addition, the grain size and the difference of grain size between the specimens sintered with bedding and without bedding was reduced with increasing SiC content. Some ultra-fine SiC particles were trapped in the Si3N4 grains growed. The number of SiC particles trapped in the Si3N4 grains increased with increasing the grain growth. When ultra-fine SiC particles were added in the Si3N4 ceramics, the strength was improved but the toughness was decreased, which was considered to be resulted from the decrease of the grain size.