| 摘要 |
PURPOSE:To obtain the title high-purity powder with high production efficiency and at a low cost by controlling the partial pressure and temp. of a nitriding gas to heat specified aluminum powder or fiber, and allowing the aluminum material to react with the gas in two steps. CONSTITUTION:The atomized aluminum powder having <=200mu particle diameter or the aluminum fiber having <=100mu diameter is used as the raw material, and 1-3wt% catalyst such as NaF and CaF2 is added, as required. The material is kept at 600-800 deg.C for >=3hr in the nitriding gas atmosphere contg. <=0.5atm partial pressure N2 or NH3, and the material is allowed to react with the gas to convert only the surface of the material into AlN. The partial pressure of the nitriding gas is then increased to >0.5atm, the temp. is increased to >800 deg.C, hence the material is allowed to react with the gas, and the whole material is nitrided. In this case, the content of the mixed impurities is adjusted to <=0.1%, and the title powder is obtained.
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