China Nonferrous Metallurgy

Microwave heating has the advantages of fast heating speed, high efficiency and low energy consumption, but it also has the shortcomings of uneven temperature field. In this paper, the temperature field uniformity of microwave heating process is theoretically simulated by applying COMSOL simulation software, and on this basis, the role of microwave heating and induction heating on the preparation of TiB₂ powder by boro/carbothermal reduction method is compared with TiB₂ B4C and carbon black as raw materials. The paper shows that the uniformity of microwave heating can be significantly improved by the arrangement of “top corner arrangement” compared with “X-axis/Y-axis diagonal arrangement” and “diagonal arrangement”; furthermore, the heating uniformity of microwave heating can be significantly improved by the arrangement of “top corner arrangement” compared with “X-axis/Y-axis diagonal arrangement” and “diagonal arrangement”. In addition, the pure-phase TiB₂ powder with uniformly distributed grains can be obtained by microwave heating at 1350℃ for 20min. Compared with induction heating (complete reaction at 1550℃), microwave heating can significantly reduce the reaction temperature, which is mainly due to the non-thermal effect of microwave. At the same time, microwave heating can refine the grain size of TiB2 from 3.95μm to 1.93μm, and can avoid the phenomenon of grain agglomeration, which in turn improves the sinterability of powder and the density of sintered materials.