A Study on the Preparation of Alumina Powders from Bauxite by Wet Acid Process and Their Utilization (III) : Effects of the Dispersion of Aluminum Hydrate Gel on the Sintering Behavior of Alumina Powder

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J. Korean Ceram. Soc. > Volume 30(4); 1993 > Article

Journal of the Korean Ceramic Society 1993;30(4): 299.

Bauxite로부터 습식 산처리법에 의한 알루미나 분체의 제조 및 그 이용에 관한 연구(III) : Aluminum Hydrate Gel의 분산에 의한 알루미나 분체의 소결성 향상

조철구, 정원도, 배원태

경상대학교 무기재료공학과

A Study on the Preparation of Alumina Powders from Bauxite by Wet Acid Process and Their Utilization (III) : Effects of the Dispersion of Aluminum Hydrate Gel on the Sintering Behavior of Alumina Powder

ABSTRACT

Dispersant was used to avoid the agglomeration of aluminum hydrate precipitate and improve the sinterability of calcined alumina powder. The mean particle size of the aluminum hydrate precipitates was 0.26${mu}{textrm}{m}$ and 0.44${mu}{textrm}{m}$ when ball-milled with and without dispersant, respectively. After calcination at 110$0^{circ}C$ for 5 hours, the size of the alumina powder without dispersant increased to 0.84${mu}{textrm}{m}$, while with dispersant slightly decreased to 0.22${mu}{textrm}{m}$. The most thermally active alumina powder was obtained from the sample calcined at 110$0^{circ}C$ for 5 hours with the 1% dispersant concentration. Using the calcined alumina powder at the above optimized condition, the specimen showed fired density of 3.94g/㎤, 4-point MOR of 364MPa, and KIC of 3.26MPam1/2 after sintered at 155$0^{circ}C$ for 3 hours.