Mechanical, electrical and thermal properties of ZrC-ZrB 2 -SiC ternary eutectic composites prepared by arc melting

ZrC-ZrB2-SiC composites were prepared by arc-melting in Ar atmosphere using ZrC, ZrB2 and SiC as starting materials. The ternary eutectic composition of 20ZrC-30ZrB2-50SiC (mol%) was first identified. SiC about 7 μm in length and 500 nm in diameter, ZrC about 4 μm in length and 1 μm in diameter, in rod-like microstructure, were uniformly dispersed in ZrB2 matrix of eutectic composite. The eutectic temperature of ZrC-ZrB2-SiC composite was approximately 2550 K. The Vickers Hardness and fracture toughness of eutectic composite was 23 GPa and 6.2 MPa m1/2, respectively. The electrical conductivity decreased from 7.2 × 107 to 1.75 × 106 S m−1 with the temperature increasing from 287 to 800 K. The thermal conductivity decreased from 85 to 61 W K−1 m−1 with increasing temperature from 287 to 973 K.