ALUMINA POWDER, PROCESS FOR PRODUCING THE SAME, AND USE THEREOF

摘要

An alumina powder to be incorporated into compositions required to have excellent thermal conductivity, such as one for radiating members and one for semiconductor encapsulation. The powder is composed of spherical alpha-alumina particles which have an average degree of sphericity of 0.93 or higher and in which at least 95 mass% of the crystal forms is accounted for by the alpha-form. The powder is produced by a process comprising a step (1) in which an aluminum metal powder or alumina powder is softened with a flame, a step (2) in which the softened powder is passed through a region having a temperature of 800-500°C to solidify it, a step (3) in which the solidified powder is passed through a region having a temperature of 950-1,500°C to heighten the alpha-phase proportion, and a step (4) in which the powder obtained is collected with cooling.