Synthesis of ZrB2 powders by carbothermal and borothermal reduction

Abstract

Zirconium diboride (ZrB2) powders were synthesized using ZrO2 + B2O3 + C (carbothermal reduction), ZrO2 + B4C (boron carbide reduction), and ZrO2 + B4C + C (combined reduction) with various compositions at 1250 degrees C for 1-3 h under flowing argon. ZrB2 powders synthesized using ZrO2 + B2O3 + C displayed rod shape growth. There was much residual impurity carbon in ZrB2 powders synthesized using ZrO2 + B4C + C. When synthesized using ZrO2 + B4C, there were the residual impurity B2O3 and little rod shape growth. Residual B2O3 impurities were easily removed by washing with methanol. We concluded that the ZrB2 powder synthesis method using boron carbide reduction is the most desirable way to produce ZrB2 powders among the three synthesis routes. ZrB2 powders synthesized using ZrO2 + B4C have a particle size of 1.1 mu m and a hexagonal shape, and low oxygen content (0.725 wt.%). (C) 2012 Elsevier B.V. All rights reserved.