| 摘要 |
PURPOSE:To obtain the titled fine powder having high bulk density and excellent dispersibility, and giving a dense sintered material, by adding a polybasic carboxylic acid (salt) to a specific aqueous solution, and carrying out the thermal hydrolysis to form colloidal particles. CONSTITUTION:An aqueous solution containing a water-soluble Zr salt or its mixture with Mg, Ca or a >=3-valent element and having a Zr salt concentration of >=0.1mol%, is added with <=0.5mol (based on 1mol of Zr) of a polybasic carboxylic acid (salt) containing 2-4 carboxylic acid groups in 1mol. The mixture is hydrolyzed to produce colloidal particles by heating at >=50 deg.C for >=several hr. Before or after the formation of the colloidal particles, the mixtur is added with an alcohol having a boiling point of >=80 deg.C (e.g. ethanol) and thermally dehydrated to obtain the titled fine powder having particle diameter of <=300Angstrom .
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