Effect of Additives of Sintering and Mechanical Properties of <TEX>$Si_3 N_4$</TEX> Bonded SiC

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J. Korean Ceram. Soc. > Volume 29(7); 1992 > Article

Journal of the Korean Ceramic Society 1992;29(7): 511.

$Si_3 N_4$ 결합 SiC의 소결과 기계적 특성에 미치는 첨가제의 영향

백용혁, 신종윤, 정종인¹, 한창

전남대학교 무기재료공학과
¹삼성전관연구실

Effect of Additives of Sintering and Mechanical Properties of $Si_3 N_4$ Bonded SiC

ABSTRACT

In this study, SiC powder and Si powder were used as the raw materials. Mixture was prepared with addition of Al2O3 and Fe2O3 at 0.1~0.5wt% respectively. After this step, the mixture was pressed and nitrided for 30 hrs at 140$0^{circ}C$ under NH3-N2 atmosphere. Mechanical properties of sintered specimens were investigated from measurement of porosity, bulk density and three point bending test. nitration reaction extent was observed at the change of mass before and after reaction, and the microstructure and the change of $alpha$-Si3N4 and $beta$-Si3N4 were observed by XRD and SEM. In the current work, the results are as follows 1. When Fe2O3 added, the nitridation increased with the content of Fe2O3, and the bending strength was increased from 0.1 wt% to 0.3 wt%, and decreased to 0.5 wt%. 2. When Al2O3 added, the nitridation and the bending strength increased little by little with the content of Al2O3 3. The bending strength of the specimen added with Fe2O3 were higher than that with Al2O3. Because the specimens contained Fe2O3 had much more the whisker type crystal of Si3N4 contributing to strength than contained Al2O3.