感应加热碳热还原合成LaB_6粉体

Synthesis of LaB_6 Powders by Combining Carbothermal Reduction and Induction Heating

以La_2O_3、B_2O_3为原料、沥青粉为还原剂,在感应炉中采用碳热还原法快速制备了LaB_6粉体。利用XRD、SEM、TEM以及激光粒度分析仪对合成的LaB_6粉体进行了表征。结果表明:在感应加热及Ar气气氛下,经1600℃保温30 min后可获得分散性好且晶粒发育良好的LaB_6粉体,其d50约为4.58μm。在感应场下加热可明显缩短反应时间,这主要是由于在高温以及感应场的协同作用下反应体系中的液相快速生成加速了物质的迁移以及B4C过渡相的析出,从而促进了LaB_6的形成。

The LaB6 powders were quickly prepared by carbothermal reduction method in induction furnace, using La203 , B203 as raw materials and pitch powder as reducing agent. The synthesized LaB6 powders were characterized by using XRD, SEM, TEM and laser particle size analysis. The results show that uniformly dispersed and the well-crystallized LaB6 powders can be obtained after induction heating at 1600 ℃ for 30 min in an Ar atmosphere, and the ds0 is about 4.58 μm. By the present earbothermal reduction method under induced field, the reaction time can be obviously shortened. Trough the synergistic effects of high temperature and induced field, the liquid phase in the reaction system can be formed rapidly. This can obviously promote the mass migration and the crystallization of B4C transition phase, leading to the rapid formation of LaB6.