Concentration of Liquid-phase in the Surface Region and Microstructural Change in Pressureless Sintered<TEX>$beta$</TEX>-SiC

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J. Korean Ceram. Soc. > Volume 33(8); 1996 > Article

Journal of the Korean Ceramic Society 1996;33(8): 921.

상압소결 $beta$-SiC에 있어서 표면부에서의 액상집중과 미세구조의 변화

이종국, 양권승, 김환¹

조선대학교 재료공학과
¹서울대학교 무기재료공학과

Concentration of Liquid-phase in the Surface Region and Microstructural Change in Pressureless Sintered$beta$-SiC

ABSTRACT

The liquid-phase concentration from the interior to the surface region and its influence on the microstructural changes were investigated in pressureless sintered $beta$-SiC Surface reaction-layer was formed by reaction of packing powder and volatile components on the surface during sintering which was induced the concentration of liquid-phase in the surface regions. The microstructural changes between the surface region and the interior were appeared in sintered specimen which was resulted from the difference of liquid-phase content during sintering. Microstructural changes were observd with the depth of about 250${mu}{textrm}{m}$ from he surface. The grain size and aspect ratio of SiC in the interior are larger than those in the surface region and the rate of transforma-tion of $beta$-to $alpha$-SiC during sintering is higher in the interior than that in the surface region.

Key words: Pressureless sintered $\beta$-SiC, Liquid-phae concentration, Microstructural change, Surface reaction-layer