| 摘要 |
PURPOSE:To obtain high purity hyperfine AlN powder having a low oxygen content and superior sinterability by mixing alumina powder with carbon in a specified ratio and by calcining the mixture in an atmosphere contg. nitrogen. CONSTITUTION:Alumina powder having >=99.9wt% purity and <=2mum average grain size is mixed with carbon having <=0.2wt% ash content and <=1mum average grain size in 1:0.4-1:1 weight ratio. The mixture is calcined at 1,400-1,700 deg.C in an atmosphere contg. nitrogen. Since the calcined product contains unreacted carbon besides produced AlN, it is preferably calcined at 650-750 deg.C in air or oxygen to oxidize and remove the residual carbon. When the oxidation temp. is excessively high, the surface of the AlN powder is excessively oxidized, so the desired powder having a low oxygen content is not obtd. The oxidation temp. and time are properly set. |
