Fabrication of Porous Alumina Mold for the Casting Process of Fine Ceramics

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J. Korean Ceram. Soc. > Volume 36(1); 1999 > Article

Journal of the Korean Ceramic Society 1999;36(1): 89.

Fine Ceramics의 Casting공정을 위한 다공질 알루미나 몰드의 제조

박한수

홍익대학교 무기재료공학과

Fabrication of Porous Alumina Mold for the Casting Process of Fine Ceramics

ABSTRACT

Manufacturing conditions of the porous alumina mold were established to overcome various limits of the gypsum mold. For the preparations of the porous alumina mold, an activated charcoal was added to the Al2O3 with the wt% variation and then mixed. The binary slurry was study dispersed based on the examination of the ESA and rheological behaviro. The cylinder type alumina mold was cast in the gyspum mold and characterized by the shrinkage rate at the variable sintering temperature and the resistance against wear. It was proper to make a sintering of the Al2O3 by the surface diffusion which was non-shrinkage sintering mechansim, and intergranular neck growed stronger while sintering was being made. We studied a sintering by three categories; 1) thermodynamic method below 1,000$^{circ}C$, 2) kinetic method above 1,000$^{circ}C$ and 3) combined method. In the results of the respective works, combined method was superiro to the others. The prepared Al2O3 mold had relatively high strength, low drying rate, the resistance against the acid or base and good casting behavior.

Key words: Alumina mold, Gypsum mold, Slip Casting, Sintering condition