Mechanical, electrical and thermal properties of HfC-HfB2-SiC ternary eutectic composites prepared by arc melting

HfC-HfB2-SiC composites were prepared by arc melting using HfC, HfB2 and SiC powder as raw materials. The ternary eutectic composition of 16HfC-17HfB2-67SiC (mol%) was first identified, showing a complicated maze microstructure of HfC, HfB2 and SiC approximately 500 nm in thickness. The eutectic temperature of the HfC-HfB2-SiC composite was nearly 2760 K. The Vickers hardness and fracture toughness of the HfC-HfB2-SiC ternary eutectic composite were 20.8 GPa and 7.7 MPa m1/2, respectively. With increasing temperature from 300 to 800 K, the electrical conductivity decreased from 8.8 × 105 to 4.3 × 105 Sm−1, whereas the thermal conductivity increased from 28 to 32 W m−1 K−1.