Characteristics of SiC Whisker-Reinforced LAS Matrix Composites Fabricated by the Mixed Colloidal Route and the Sol-Gel Process

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J. Korean Ceram. Soc. > Volume 28(12); 1991 > Article

Journal of the Korean Ceramic Society 1991;28(12): 1012.

콜로이드 혼합법 및 Sol-Gel 법에 의해 제조한 SiC 휘스커 강화 LAS 기지 복합체의 특성

김광수, 장현명¹, 정창주, 백용기²

전남대학교 공과대학 무기재료 공학과
¹포항공과대학 재료공학과 정밀 세라믹스 공정과학 연구실
²국방과학 연구소 소재 개발부 소재 2실

Characteristics of SiC Whisker-Reinforced LAS Matrix Composites Fabricated by the Mixed Colloidal Route and the Sol-Gel Process

ABSTRACT

SiC whisker-reinforced LAS matrix composites were developed by a mixed colloidal processing route. An optimization of processing conditions was made using the zeta potential data of silica, boehmite, and SiC whisker dispersions. Similarly, the SiC whisker-reinforced composites were also fabricated by the conventional sol-gel process using the hydrolysis-condensation reaction of relevant metal alkoxides. The composites fabricated by the mixed colloidal processing route were characterized by a uniform spatial distribution of SiC whisker throughout the matrix. The fracture toughness increased from 1.3 MPa.m1/2 for the LAS specimen to 5.0 Mpa.m1/2 for the hot-pressed composite (95$0^{circ}C$ and 20 MPa for 20 min) containing 20 wt% SiC whisker. The increase in fracture toughness appears to result mainly from the crack deflection and the crack bridging by whiskers with some additional toughenings from the whisker pullout and the matrix prestressing mechanisms.