A Study on the Fabrication and Mechanical Properties of <TEX>$WC-Co-Al_2O_3$</TEX> Ceramic Composites Using WC Powders Synthesized by SHS Method and Commercial WC Powders

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J. Korean Ceram. Soc. > Volume 32(12); 1995 > Article

Journal of the Korean Ceramic Society 1995;32(12): 1392.

SHS 화학로법에 의해 합성된 WC 분말과 상용 WC 분말을 이용한 $WC-Co-Al_2O_3$ 세라믹 복합체의 제조 및 그 기계적 특성에 관한 연구

이강렬, 조덕호¹, 이형복, 박성

명지대학교 무기재료공학과
¹요업기술원

A Study on the Fabrication and Mechanical Properties of $WC-Co-Al_2O_3$ Ceramic Composites Using WC Powders Synthesized by SHS Method and Commercial WC Powders

ABSTRACT

WC-10wt%Co-Al2O3 ceramic composites, using both the SHS (Self-propagating High Temperature Synthesis) synthesized WC powder method and commercial WC powder, were prepared by varing WC-Co/Al2O3 vol% ratio and sintering temperature (1350℃∼1650℃) for 1 hr in Ar atmosphere. Mechanical characterization has been investigated by Instron meterial testing system and Vicker's hardness test. Compositional and structural chracterizations were carried out by energy-dispersive analysis of X-ray (EDAX) data and scanning electron microscope (SEM). Electrical characterization was carried out by the electrical resistivity measurement using 4-point probe method. As sintering period increased and Al2O3 contents decreased in WC-10wt%Co-Al2O3 ceramic composite, shrinkage and relative density increased, resulting in maximum values at 1600℃. Also the major matrix phase changed with increasing Al2O3 content from 0 to 100 vol%. It was also identified by SEM, EDAX, and electrical resistivity measurement. Based on the results of analysis of flexural strength, toughness and hardness, the mechanical properties of WC-10wt%Co-Al2O3 ceramic composites using the SHS synthesized WC powder were better than those WC-10wt%Co-Al2O3 ceramic composites using commercial WC powder because WC-10wt%Co-Al2O3 ceramic composites using the SHS synthesized WC powder were sintered very well due to small initial particle size. By the addition of 40 vol% Al2O3 [60(WC=10wt%Co)-40Al2O3], it was possible to obtain a proper candidate as a superalloy.

Key words: WC, SHS method, $WC-10wt%Co-Al_2O_3$ ceramic composites, Superalloy