Effects of HBO2 on phase and morphology of ZrB2 powders synthesized by carbothermal reduction

Zirconium diboride (ZrB2) powders were synthesized by carbothermal reduction with ZrO2, HBO2, and carbon black as raw materials. The effects of reaction temperature and HBO2 content on the phase and morphology of ZrB2 powders were investigated. The phase composition was characterized by X-ray diffraction (XRD) and the micromorphology was observed by scanning electron microscope (SEM). The thermodynamic reaction process was studied. When the amount of HBO2 was 60 wt%, pure ZrB2 powders could be obtained, as indicated by XRD results. Hexagonal ZrB2 particles ranging from 1 to 2 mu m could be successfully prepared at 1600 degrees C in Ar atmosphere while adding 30 wt% NaCl.