Behaviors of Abnormal Expansion in <TEX>$Ba_2Ti_9O_{20}$</TEX> Ceramics during Calcination Process

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J. Korean Ceram. Soc. > Volume 36(12); 1999 > Article

Journal of the Korean Ceramic Society 1999;36(12): 1327.

$Ba_2Ti_9O_{20}$ 요업체의 하소공정중 이상팽창 거동

성제홍, 김정주, 김남경, 조상희

경북대 무기재료공학과

Behaviors of Abnormal Expansion in $Ba_2Ti_9O_{20}$ Ceramics during Calcination Process

ABSTRACT

Behaviors of abnormal expansion during calcination process of Ba2Ti9O20 ceramics and its related effects on the sintering characteristics were investigated as a function of precursors. When BaCO3 and TiO2 powders were used as starting materials. BaTi4O9 phase which has relatively large molar volume was formed drastically with abnormal ex-pansion during the calcination at 95$0^{circ}C$ to 115$0^{circ}C$ ON the contrary using BaTiO3 and TiO2 powders as starting materials led to retardation of the formation of BaTi4O9 phase and concurrently suppressed the abnormal expansion during cal-cination process. Especially the calcined powder of BaTiO3 and TiO2 had advantages in the densification and formation of Ba2Ti9O20 single phase in the sintering process.

Key words: Abnormal expansion, $Ba_2Ti_9O_{20}$, Calcination, $BaTi_4O_9$, $BaTiO_3$