Hot‐Pressed ZrB 2 Ceramics With Composite Additives of Zr and B 4 C

This work pointed out a new approach to get dense ZrB 2 ceramics by forming refractory second phases through adding reactive composite additives. With the combination of Zr and B 4 C additives at a 3:1 molar ratio, the densification, microstructure, and mechanical properties of hot‐pressed ZrB 2 ceramics were investigated. The Zr reacted with B 4 C at relatively low temperature of 1400 °C to form the secondary ultra‐high‐temperature ZrB 2 and ZrC phases with high sinterability, which would be beneficial to improve the densification and maintain the high‐temperature properties of ZrB 2 ceramics. For comparison, the separate effects of B 4 C or Zr additive on densification and microstructures of ZrB 2 ceramics were also investigated.