Abstract: A sinterable aluminum nitride powder composition is prepared by adding about 0.05-10.0 parts by weight of at least one compound selected from the group consisting of calcium tungstate and calcium molybdate and optionally about 1.0-7.0 parts by weight of at least one compound selected from the group consisting of yttria, calcium oxide, and calcium carbonate to 100 parts by weight of an aluminum nitride powder prepared by the alumina reduction method without decarbonization and having a residual carbon content of about 2%-10% by weight. The resulting powdery composition is subjected to mixing and deagglomeration in a dry process so as to form a powder mixture having a bulk density of about 0.3-0.5 g/cm.sup.3, and then to decarbonization by heating in an oxidizing atmosphere. The aluminum nitride powder composition has a pressurized bulk density of about 1.50-1.75 g/cm.sup.3 as measured at a pressure of 500 kg/cm.sup.2 and an average particle diameter of about 1.0-3.0 .mu.

Abstract: A process for producing an aluminum nitride powder by reacting a mixture of alumina and carbon with a nitrogen gas, wherein the mixture of alumina and carbon being contacted with a nitrogen-containing inert gas at a temperature of 1,000.degree. to 1,400.degree. C. at a pressure of not higher than 0.1 atmosphere before a reaction is started to form aluminum nitride.