• Korean Journal of Materials Research
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• v.9 no.8
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• pp.843-848
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• 1999

The efect of A1 addition and sintering condition on mutization behavior between alumina and silica in alumina-based shell mold was investigated. A1 addition and high sintering temperature increased the degree of mullitization between alumina/silica but decreased the room temperature strentgh of the shell molds. It was identified that the sintered strength of the shell molds was in range of 2.0~2.6kg/$\textrm{mm}^2$. Al addition suppressed deflection of the shell molds at high temperature. Especially, no deflection was observed in the specimen which was sintered at $1000^{\circ}C$ for 1hr with 2.5wt% Al. The specimen sintered at $1500^{\circ}C$ for 4hrs with no Al addition also displayed no deflection.