Preparation of nano-ZrB 2 powder by Ca liquid assisted boronation reaction between ZrC and B 4 C

Nano-Zirconium diboride (ZrB 2 ) powder was vital raw material for manufacturing ultra-high temperature ceramics (UHTCs) and C/C composite materials, which were widely used in extreme environment. In this paper, a convenient way of synthesizing nano-ZrB 2 powder was proposed. Firstly, the precursor consisting of ultrafine-ZrC and C was obtained via vacuum carbothermal reduction of nano-ZrO 2 . And then, the carbothermal reduction product was boronized by B 4 C in Ca melt. In boronation process, Ca melt would play a key role as decarburizer. By boronation reaction at 1373 K and 1473 K, cauliflower-shaped ZrB 2 particle and smooth polyhedral ZrB 2 particle were obtained, respectively. XRD and BET analyses showed that the grain sizes and BET-equivalent particle diameters of these two products were less than 100 nm.