Microstructure and properties of ZrB2–SiC composites prepared by spark plasma sintering using TaSi2 as sintering additive

ZrB2–SiC composites were fabricated by spark plasma sintering (SPS) using TaSi2 as sintering additive. The volume content of SiC was in a range of 10–30% and that of TaSi2 was 10–20% in the initial compositions. The composites could be densified at 1600 °C and the core–shell structure with the core being ZrB2 and the shell containing both Ta and Zr as (Zr,Ta)B2 appeared in the samples. When the sintering temperature was increased up to 1800 °C, only (Zr,Ta)B2 and SiC phases could be detected in the samples and the core–shell structure disappeared. Generally, the composites with core–shell structure and fine-grained microstructure showed the higher electrical conductivity and Vickers hardness. The completely solid soluted composites with coarse-grained microstructure had the higher thermal conductivity and Young's modulus.