Synthesis of rod-like ZrB2 crystals by boro/carbothermal reduction

Rod-like ZrB 2 crystals were synthesized at 1600 °C in Ar atmosphere by boro/carbothermal reduction using ZrOCl 2 ⋅8H 2 O, B 4 C and carbon powders as raw materials. The optimum molar ratio of raw materials required to form pure ZrB 2 grains was found to be 2: 1.2: 3. With increase in temperature and subsequent heat preservation stage, ZrB 2 powders grew into a rod-like morphology along the c axis. The rod-like ZrB 2 grains obtained at 1600 °C have diameters of 0.5–3 μm and high aspect ratios of >8. Effects of molar ratio of raw materials, heating temperature and holding time on the phase composition and final morphology were investigated. Growth mechanism of rod-like ZrB 2 grains was also analyzed.