Effect of <TEX>$Zn_7Sb_2O_{12}$</TEX> Content on Grain Growth and Microstructure of ZnO Varistor

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J. Korean Ceram. Soc. > Volume 30(11); 1993 > Article

Journal of the Korean Ceramic Society 1993;30(11): 955.

$Zn_7Sb_2O_{12}$ 첨가량이 ZnO 바리스터의 입자성장과 미세구조에 미치는 영향

김경남, 한상목

강원대학교 재료공학과

Effect of $Zn_7Sb_2O_{12}$ Content on Grain Growth and Microstructure of ZnO Varistor

ABSTRACT

Sintering behavior and microstructure development in the system ZnO-Bi2O3-CoO-Zn7Sb2O12 with Zn7Sb2O12 content(0.1mol%~2mol%) were studied. The pyrochlore phase was formed by the reaction of the Zn7Sb2O12 with Bi2O3 phase during heating (below 90$0^{circ}C$). The formation temperature of the liquid phase (Bi2O3) was dependent on the Zn7Sb2O12 contents (about 74$0^{circ}C$ for Bi2O3/Zn7Sb2O12>1 by the eutectic melting in the ZnOBi2O3 system, and about 110$0^{circ}C$ for Bi2O3/Zn7Sb2O12 1 by the decomposition of pyrochlore phase). Hence, sintering behavior and microstructure development were determined virtually by the Bi2O3/Zn7Sb2O12 ratio, which were promoted by liquid (Bi2O3) phase and retarded by the pyrochlore (or spinel) phase. The grain growth of ZnO during sintering was sluggish with increasing Zn7Sb2O12 contents.