| 摘要 |
PURPOSE:To prepare high purity ceramic powder such as fine aluminum silicate powder, by adjusting the pH of a solution of Al alkoxide or an Al salt and Si alkoxide in a nonaqueous solution in two stages, i.e. acidic and then basic, thereby hydrolyzing the compounds. CONSTITUTION:The alkoxide of formulaIor an Al salt and the alkoxide of formula II are pretreated so as to afford the produced aluminum silicate to take a mullite structure, and then dissolved in a nonaqueous solvent (e.g. ethanol). The pH of the solution is adjusted to <=5, especially <=2 by adding hydrochloric acid, etc., and then to >=8, especially to >=10 by slowly adding ammonia water. Hydrolysis and gelatinization take place by the pH adjustment forming aluminum silicate. The product is washed with water or an alcohol, dried, and again heated to about 600 deg.C to obtain the objective fine powder of high purity ceramic. The compound of formulaIis e.g. Al(OCH3)3, and that of the formula II is, e.g. Si(OC2H5)4. |
