ZHANG Lina, WANG Qi, FANG Minghao, MIN Xin, LIU Yan’gai, WU Xiaowen, HUANG Zhaohui
(Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid Wastes, National Laboratory of Mineral
Materials, School of Materials Science and Technology, China University of Geosciences (Beijing), Beijing 100083, China)

Abstract: Al₂O₃-SiC composite powders were designed and synthesized by using coal gangue produced by Shuozhou of Shanxi Province as the main raw material and coke, anthracite and carbon black as the reducing agents. The effects of calcined temperature, holding time and reducing agents on Al₂O₃-SiC powder preparing were discussed. The phase composition and microstructure of the synthesized products were analyzed by XRD and SEM. The XRD results indicated that, using coke and anthracite as reductors, the optimum preparation parameters were 1600 °C heat soaking for 5 h; changing the reductor to carbon black, the optimum preparation parameters were 1600 °C heat soaking for 4 h . The SEM results indicated that the Al₂O₃-SiC composites prepared with different reducing agents had different microstructure, and the bonding modes between Al₂O₃ and SiC were not the same. The main reason was that the high temperature reaction of coal gangue with carbon black produced gas phase SiO while its reaction with coke and anthracite resulted in the formation of liquid phase SiO₂. The two reaction processes were different.

Key words: coal gangue; Al₂O₃-SiC; composite powder