Low-Temperature Rapid Synthesis of Rod-Like ZrB₂ Powders by Molten-Salt and Microwave Co-Assisted Carbothermal Reduction

A novel molten-salt and microwave coassisted carbothermal reduction (termed as MSM-CTR) method was developed to prepare ZrB ₂ powders from raw materials of ZrO ₂ , B ₄ C, and amorphous carbon. The results indicated that the carbothermal reduction reaction for synthesizing ZrB ₂ was initiated at the temperature as low as 1150⁰C, and phase pure ZrB ₂ powders were obtained after only 20 min at 1200⁰C, which were significantly milder than that of the conventional CTR method as well as the modified CTR method even using active metal as additional reducing agents. More interestingly, the as-obtained ZrB ₂ powders consisted of well-defined single-crystalline nanorods, which had diameters of 40–80 nm and high aspect ratios of >10. These results demonstrated that the MSM-CTR is a simple and efficient route for preparation of high-quality ZrB ₂ powders.