Cubic AlN Synthesized by High Energy Ball Milling and Its Phase Conversion at High Temperature

The phase conversion of Al2O3 during high-energy ball milling was investigated. After 20h milling, amorphous and A1N were observed in powders, these were not reported previously. The crystal structure of AlN gained during ball milling is cubic, differs from that of the regular hexagonal A1N synthesized with carbothermal reduction. AlON phase forms by the reaction of cubic AlN andγ-Al2O3 after annealing in N2 atmosphere at the temperature above 500℃. The formation of AlON phase decreases the commencing temperature of AlN.