Mechanical Properties of <TEX>$beta$</TEX>-Sialon Ceramics Prepared from Wando Pyrophyllite and an Alkoxide

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J. Korean Ceram. Soc. > Volume 28(5); 1991 > Article

Journal of the Korean Ceramic Society 1991;28(5): 390.

완도납석과 알콕사이드로부터 제조된 $beta$-Sialon 세라믹스의 기계적 성질

이홍림, 손연하, 임헌진

연세대학교 요업공학과

Mechanical Properties of $beta$-Sialon Ceramics Prepared from Wando Pyrophyllite and an Alkoxide

ABSTRACT

$beta$-Sialon powder was prepared from Wando pyrophyllite by the carbothermic reduction and nitridation at 135$0^{circ}C$ for 10 h nitrogen atmosphere. Amorphous silica prepared from Si(OC2H5)4 was added to Wando pyrophyllite powder in order to control the final Z value. Two different methods were applied for synthesis of $beta$-sialon powders. In Process A, the amorphous silica prepared from Si(OC2H5)4 was admixed to Wando pyrophyllite powder. Process B was started from the mixture of Wando Y2O3 was added to the synthesized $beta$-Sialon powders as a sintering aid, and the mixed powders were hot pressed at 175$0^{circ}C$ for 120 min in nitrogen atmosphere under 30 MPa. Their mechanical properties were compared. The maximum values of M.O.R., hardness and KIC were 667 MPa, 16 GPa and 6.3 MN/m3/2, respectively, and they are the values obtained form $beta$-Sialon ceramics prepared by process A of Z=0.5.