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

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.