| 摘要 |
PURPOSE:To produce the title powder having high purity and hyperfine particle size which can provide a sintered body having high density, high purity, superior translucent, thermal characteristics, and mechanical characteristics without requirement for additive by calcining a compsn. of a mixture of Al2O3 powder having a specified purity and particle size with carbon in the atmosphere contg. N2. CONSTITUTION:(A) Al2O3 powder having >=99.9% purity and <=2mu mean particle size is mixed with (B) carbon having <=0.2wt.% ash content and <=1mu mean particle size at 1/0.4-1 (A/B) ratio (proportion by weight) in a ball mill comprising a ball and vessel made of alumina of high purity by such as wet mixing process to obtain thus a mixture compsn. Then, the mixture is charged to a calcining furnace where it is calcined at 1,400-1,700 deg.C for 3-10hr in the atmosphere contg. N2 to which gaseous N2 and, if necessary, gaseous NH3 are added. Thus, the title powder having <=2mu mean particle size is obtd. at <=1.3wt.% O2 content and <=0.3wt.% cationic impurities.
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