In Situ Synthesis of ZrB2–SiC Composite Powders by Carbothermal Reduction Method

Abstract

ZrB2–SiC composite powders were synthesized in situ via carbothermal reduction using ZrO2, HBO2 and carbon black as the starting materials. The influences of HBO2 contents (40.6–45.5 wt%), boron sources (HBO2, H3BO3 and B2O3) and carbon sources (black carbon, activated carbon, graphite and petroleum coke) on phase composition and morphology of ZrB2–SiC composite powders were analyzed. The obtained samples were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results showed that when the HBO2 content was 43.2 wt%, impurity-free ZrB2–SiC composite powders could be successfully produced at 1600 °C for 90 min in argon atmosphere. Meanwhile, columnar ZrB2 and granular SiC particles were combined interactively. Compared with control groups, products fabricated via black carbon revealed the better crystallinity and finer particle size.