| 摘要 |
PURPOSE:To suppress the amounts of magnesia and to produce extremely high purity alumina ceramics by restraining the intrusion of an alikali metal into alumina and other raw materials as much as possible in the production of the alumina ceramics. CONSTITUTION:In the production of the alumina ceramics for semiconductor production device, the magnesia which is an abnormal particle growth inhibitor for the alumina can be lessened by decreasing the contents of the alkali metal, thus the extremely high purity alumina ceramic material is obtained. Therefor, the highent-purity alumina is used as a raw material, and pure water is used for the processing water, and also an acrylic or maleic acid polymer is used as a molding additive, and by preventing contamination caused by the alkali metal in the molding process and the firing process, the high purity alumina ceramics in which the alkali oxide is <=50ppm and the magnesia is <=100ppm is obtained. |
