Interfacial Characterization of <TEX>$beta$</TEX>-Sialon Powder Prepared from Hadong Kaolin

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

Journal of the Korean Ceramic Society 1992;29(7): 551.

하동 카올린으로부터 제조한 $beta$-Sialon 분체의 계면특성

임헌진, 이홍림

연세대학교 세라믹공학과

Interfacial Characterization of $beta$-Sialon Powder Prepared from Hadong Kaolin

ABSTRACT

X-ray diffraction patterns, IR spectra and zeta-potentials of silicon nitride and $beta$-Sialon powders were investigated before and after surface manipulations. $beta$-Sialon powder was produced from Hadong Kaolin by the carbothermic reduction and simulataneous nitridation. Isoelectric points of as-prepared Si3N4 and $beta$-Sialon powders were 8.4 and 7.4, respectively. After both silicon nitride and $beta$-Sialon powders were oxidized at 80$0^{circ}C$ for 24 h in air, the isoelectric points of these powders corresponded to that of silica (pH=3). I case of the addition of Darvan C as deflocculant, its isoelectric point was 3 and zeta-potential was nearly constant in the range of pH 5~12. When SN 7347 was used as deflocculant, its isoelectric point was 8.3 and zeta-potential over -156 mV was measured above pH 11.