Synthesis of Al N from Al_2O_3 activated by plasma assisted ball milling
DAI Le-yang;ZHANG Bao-jian;LIN Shao-fen;LIU Zhi-jie;WANG Wen-chun;Fujian Provincial Key Laboratory of Naval Architecture and Ocean Engineering,Institute of Marine Engineering, Jimei University;Department of Materials Science and Engineering, North Carolina State University;Key Laboratory of Materials Modification, Ministry of Education,Dalian University of Technology;
The synthesis mechanism of Al N 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 Al N 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 k J/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.