Preparation of Monophasic Tungsten boride powder from Tungsten and boron carbide

Tungsten borides are special compounds with potential applications in superhard materials, anti-friction materials, and catalytic materials. In this study, a new synthetic method for tungsten boride is proposed using tungsten (W) and boron carbide (B4C) as raw materials. First, the boronization reaction between W and B4C was carried out at a high temperature; then, the boronization products were reacted with calcium to generate CaC2 for decarburization. After acidic leaching of the CaC2 and Ca, pure tungsten boride could be prepared. By investigating the reaction between different ratios of W and B4C, it was found that only pure W2B and WB were synthesized in the current method, and W2B5 could react rapidly with Ca to form WB and CaB6. However, in the absence of a decarburization treatment after the boronization process, carbon-containing WB (C content = 1.2 wt%) and W2B5 (C content = 3.4 wt%) could also be prepared. In addition, it was concluded that the prepared tungsten boride roughly maintained the morphology and particle size of raw W, and ultra-fine tungsten boride could be synthesized with ultra-fine W powder at a low boronization reaction temperature.