| 摘要 |
PURPOSE:To obtain the porous ceramics of an alumina system having a high specific surface area at a high temp. by hydrolyzing a precursor mixture, which is obtd. by mixing a specific reforming agent and silicon alkoxide into alumina alkoxide, and gelatinizing the mixture, then calcining this gel after supercritical drying. CONSTITUTION:The precursor mixture of the alumina system is formed by mixing 0.1 to 5 times mol one or >= 2 kinds of alkanol amine, beta ketoate and betadiketone compd. (reforming agent) and 0.1 to 3mol% silicon alkoxide into the aluminum alkoxide. The precursor mixture is the hydrolyzed and gelatinized with water of 0.5 to 2 times the mol of the number of the reaction groups which exist in the above-mentioned mixture and are obtd. by hydrolyzing in the presence of a basic catalyst at need. The gel is dried by way of the supercritical state of the org. solvent occupying the greater part of the liquid component in the gel or the mixed system contg. this org. solvent. The dried gel is subjected to a heating treatment in a nonoxidative atmosphere. |
