Study on Phase Conversion and Reactivity of Al_2O_3 during High Energy Ball Milling

The crystal structure conversion and reactivity of Al_2O_3 during high-energy ball milling was investigated in this paper.γ-Al_2O_3,which with high reaction activation transforms to α-Al_2O_3 along with ball milling and heating up process.After 20 hours milling,amorphous and AlN were observed in powder,these have not been reported previously.The active carbon powder added for carbothermal reduction restrains the phase transformation of γ-Al_2O_3,and preserves the reactivity effectively.