The Effect of Nitride Coating on SiC Platelet in <TEX>$Al_2O_3/SiC$</TEX> Hybrid-Composite

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J. Korean Ceram. Soc. > Volume 34(4); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(4): 406.

$Al_2O_3/SiC$ Hybrid-Composite에서 SiC에 질화물 코팅의 영향

이수영, 임경호¹, 전병세¹

한국기계연구원 요업재료그룹
¹경남대학교 무기재료공학과

The Effect of Nitride Coating on SiC Platelet in $Al_2O_3/SiC$ Hybrid-Composite

ABSTRACT

Al2O3/SiC hybrid-composite has been fabricated by the conventional powder process. The addition of $alpha$-Al2O3 as seed particles in the transformation of ${gamma}$-Al2O3 to $alpha$-Al2O3 provided a homogeneity of the microstructure. The grain growth of Al2O3 are significantly surpressed by the addition of nano-size SiC particles. Dislocation were produced due to the difference of thermal expansion coefficient between Al2O3 and SiC and piled up on SiC particles in Al2O3 matrix, resulting in transgranular fracture. The high fracture strength of the composite was contributed to the grain refinement and the transgranular fracture mode. The addition of SiC platelets to Al2O3/SiC nano-composite decreased the fracture strength, but increased the fracture toughness. Coated SiC platelets with nitrides such as BN and Si3N4 enhanced fracture toughness much more than non-coated SiC platelets by enhancing crack deflection.

Key words: hybrid-composite, nano-composite, SiC platelet