To produce alumina particles having a fine particle size of the order of nanometers and excellent heat resistance at about 1,000°C.
A liquid containing not only particles made of γ-alumina or boehmite alumina hydrate but also a metal component such as La, Ba, Mg or the like is provided, and the particles and the metal component are heat-treated in the presence of the liquid under pressure. The heat-treated particles are dried and sintered at a temperature of ≥900°C and <1,200°C to produce alumina particles having a metal aluminate crystal phase on their surface. Since the metal component is allowed to form a solid solution on the surface of the alumina particles by performing the heat treatment prior to sintering, the metal aluminate crystal phase having excellent heat resistance can be formed by sintering at a temperature lower than an ordinary sintering temperature. As a result, the particle size is prevented from increasing during sintering, so that the alumina particles having a fine particle size of the order of nanometers and excellent heat resistance can be obtained.
COPYRIGHT: (C)2010,JPO&INPIT
Miho Ito
Tomoya Itakura
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