Pressureless-sintering of Silicon Carbide with Additiions of Yttria and Alumina

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J. Korean Ceram. Soc. > Volume 26(2); 1989 > Article

Journal of the Korean Ceramic Society 1989;26(2): 228.

Yttria-alumina계 소결조제를 이용한 탄화규소의 상압소결

김도형, 장철우, 박병학, 백성기

산업과학기술연구소 무기재료연구분야

Pressureless-sintering of Silicon Carbide with Additiions of Yttria and Alumina

ABSTRACT

Pressureless-sintering of SiC with additions of yttria and alumina was studied. SiC could be densified to about 97% of its theoretical density at 185$0^{circ}C$ which is about 20$0^{circ}C$ below the normal sintering temperature of SiC with boron and carbon. Yttria and alumina formed intergranular liquid phases at the sintering temperature and promoted densification by the liquid phase sintering mechanism. The microstructure of sintered specimens was equiaxed and the liquid phase appeared to wet and dissolve SiC grains. The fracture toughness was measured by indentation method and found to be 5.3MPa.m1/2. Processing flaws near the surface of specimens appeared to be the major fracture origin during 3-point bending tests.