| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide low-soda spherical alumina powder excellent in moisture resistance reliability, thermal conductivity, packing properties and wear resistance, and suitable as a filler. <P>SOLUTION: In the spherical alumina powder sphered by thermal-spraying alumina raw material powder containing a soda component produced by a Bayer process into flame, the surface of the spherical alumina powder is provided with a silica coating layer using silica fine powder having the average particle diameter of <2 μm and the specific surface area of 10-25 m<SP POS="POST">2</SP>/g, and the content of soda in an extract extracted from the surface of the spherical alumina powder at ordinary temperature is ≤40 ppm. <P>COPYRIGHT: (C)2013,JPO&INPIT |
