Synthesis of AlN from Al₂O₃ activated by plasma assisted ball milling

The synthesis mechanism of AlN by Al₂O₃ powders through carbothermic reduction reaction was investigated, in which the Al₂O₃ powders was activated by plasma assisted ball milling (PM) or by conventional ball milling (CM). The results indicate that Al₂O₃ powders activated by plasma assisted ball milling for 40 h can be converted to AlN totally through carbothermic reduction reaction when annealed at 1400℃ for 4h in N₂. It is gas reaction mechanism for the carbothermic reduction reaction of Al₂O₃ powders after plasma assisted ball milling. The subsequent reaction temperature of Al₂O₃ powders is reduced significantly because the reaction activation energy decreases to 371.5 kJ/mol after plasma assisted ball milling for 40 h. A lot of lattice distortions are generated in Al₂O₃ grain due to the cooperation of plasma and ball milling, which is an important factor for promoting the carbothermic reduction reaction of Al₂O₃ powders activated by plasma assisted ball milling.