| 摘要 |
PURPOSE:To obtain the composition for a mullite sintered body which is excellent in degree of sintering and mechanical strength by mixing specified mullite raw material powder with cerium oxide and thereafter calcining the mixture. CONSTITUTION:The aimed sintered body is obtained by uniformly mixing mullite raw material powder wherein alumina to silica is regulated to (65:35)-(80-20) (weight ratio) or 95-99.8wt.% mullite powder pulverized after calcining thin mullite raw material powder with 0.2-5wt.% cerium oxide powder or with salt or an organic compd. contg. 0.2-5wt.% cerium oxide and thereafter calcining the mixture. As the mullite raw material powder, when ratio of alumina to silica is deviated from the above-mentioned range, strength is deteriorated at high temp. and the aim cannot be achieved. Cerium oxide does not react with alumina and silica of the mullite raw material powder but exists as cerium oxide crystal, and softening is hardly caused by existence of cerium oxide crystal and deterioration of strength at high temp. is made small and also sintering temp. can be lowered. |
