高温固相反应合成硼化钨粉体

Preparation of Tungsten Boride Powder by High-Temperature Solid-State Reaction

摘要:

以硼和钨为原料在真空碳管炉中进行高温合成硼化钨，研究了B/W摩尔比、温度及合成时间对产物的影响。采用XRD、SEM对产物的物相组成与微观形貌进行分析，结果表明：当B/W摩尔比为2时产物主要为WB与WB2，当B/W摩尔比增加至2.5，且温度在1400 ℃以上可以得到纯度较高的WB2；当B/W摩尔比大于4时，产物主要为WB2与WB4，WB4的相对含量随反应时间的延长而增加。根据产物的形貌，物相组成和能谱分析建立了WB4的合成路径示意图。

Abstract:

Through a solid-state reaction, tungsten borides were synthesized from boron and tungsten powders under vacuum in a graphite element furnace. In particular, the effects of B/W mole ratio, the temperature and the holding time on the products were investigated. The phase composition and morphology of the product were further analyzed by XRD and SEM, respectively. The result shows that the main products are WB and WB2 when the B/W ratio is controlled to be 2; however, when the ratio is increased to 2.5 above 1400 oC WB2 of high purity can be obtained. With the B/W ratio more than 4 the main products are mixed by both WB2 and WB4. The relative content of WB4 is increased with prolonging the annealing time. The model of WB4 formation process has been discussed.