Phase Analysis and Fracture Toughness of <TEX>$Si_3N_4$</TEX>-Zr(Y)<TEX>$O_2$</TEX>  Composites after Heat Treatment

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J. Korean Ceram. Soc. > Volume 28(1); 1991 > Article

Journal of the Korean Ceramic Society 1991;28(1): 53.

$Si_3N_4$-Zr(Y)$O_2$ 복합체의 열처리에 따른 상분석 및 파괴인성

김재룡, 김종희

한국과학 기술원 재료공학과

Phase Analysis and Fracture Toughness of $Si_3N_4$-Zr(Y)$O_2$ Composites after Heat Treatment

ABSTRACT

The reaction product between Si3N4 and ZrO2 has been studied by heat treatment of Si3N4-Zr(Y)O2 composite in high vacuum(<10-5 torr) and in air at $700^{circ}C$. ZrN was formed after heat treatment in vacuum and easily oxidized after heat treatment in air. The amount of ZrN is related to the Y2O3 content dissolved in ZrO2. After the heat treatment in air the toughness increased and the spalling due to the oxidation of ZrN in specimen surface was observed. As a result, it is suggested that the formation of ZrN phase in Si3N4-ZrO2 composite enhance the toughness of the composite in an oxidation conditon.