HIGHLY DISPERSIBLE HIGH SPHERICITY ALUMINUM OXYNITRIDE POWDER, METHOD AND APPARATUS FOR MANUFACTURING THE SAME

PROBLEM TO BE SOLVED: To provide novel high sphericity aluminum oxynitride powder and a method and an apparatus for manufacturing the same. SOLUTION: The aluminum oxynitride powder in which it is attained simultaneously that the grain growth of raw material powder is suppressed to have a primary particle diameter ranging from 0.05 μm to 100 μm, the melting, solidification or aggregation of a product is prevented and high dispersibility and/or the rounded external shape of the particles are exhibited is manufactured using a manufacturing method and a manufacturing apparatus for advancing an oxynitride reaction in a vapor phase in the presence of flame by controlling the following technical requirements at the same time, that is (1) the adjustment of gaseous atmosphere in the flame and the stabilization of the inner flame or a reduction combustion flame, (2) the utilization of a direct nitriding method or a reduction nitriding method using heat energy by the flame as driving force, (3) the formation of vapor phase dispersion (an aerosol state) of the raw material powder and the efficient supply to the reaction field and (4) the ratio control of the raw materials and the flame quantity or the continuity of a heat treatment process. Then the particle diameter and the sphericity necessary as a sintered compact raw material powder in an optical material utilizing translucency by an isotropic crystal structure or a melting resistant material utilizing high thermal shock resistance and the low wettability/low reactivity to molten steel are attained simultaneously.