| 摘要 |
PROBLEM TO BE SOLVED: To provide high purity spherical alumina powder having more improved reliability to moisture resistance, a method for manufacturing the same and a composition obtained by using the powder. SOLUTION: The high purity spherical alumina powder contains≤30 ppm of Na<SP>+</SP>and≤50 ppm, in total, of ionic impurities. In the method for manufacturing the high purity spherical alumina powder, raw alumina powder in which a content of particles having a sphericity of≥0.90 is≥90 mass% is washed with water of pH 3-7 substantially free from Na<SP>+</SP>, K<SP>+</SP>, NH<SB>4</SB><SP>+</SP>, Mg<SP>2+</SP>and Ca<SP>2+</SP>. The composition is obtained by incorporating the high purity spherical alumina powder into at least one of rubber and resin. COPYRIGHT: (C)2006,JPO&NCIPI
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