Synthesis of <TEX>$alpha-Al_2O_3/SiO_2$</TEX> Composite Powders for Reaction-Sintered Mullite and its Properties

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J. Korean Ceram. Soc. > Volume 32(8); 1995 > Article

Journal of the Korean Ceramic Society 1995;32(8): 909.

반응소결 물라이트를 위한 $alpha-Al_2O_3/SiO_2$ 복합분말의 합성 및 그 특성

김희수, 이종국¹, 김환

서울대학교 무기재료공학과
¹조선대학교 재료공학과

Synthesis of $alpha-Al_2O_3/SiO_2$ Composite Powders for Reaction-Sintered Mullite and its Properties

ABSTRACT

From alumina powder and TEOS, $alpha$-Al2O3/SiO2 composite powder for reaction-sintered mullite was synthesized by heterogeneous coagulation and surface coating, and investigated the mullitization reaction and sintering behavor of these powders. In $alpha$-Al2O3/SiO2 composite powder prepared by heterogeneous coagulation, each alumina particles were surrounded by silica particles of 50~60 nm in size. And the alumina particles in composite powder prepared by surface coating were coated by uniform silica layer with thickness of 50 nm. In both methods, mullitization reaction was completed at 1$650^{circ}C$ for 3h, and specimen sintered above 145$0^{circ}C$ was about 95% fo the theoretical relative density. Mullite grains formed from the reaction with composite powders showed spherical shape with a size of 1~2${mu}{textrm}{m}$.

Key words: \$alpha-Al_2O_3/SiO_2$ composite powder, Heterogeneous coagulation, Surface coating, Reaction-sintered mullite