Preparation of ZrB2-SiC composites by arc melting and their properties

Abstract

ZrB 2 -SiC composites were prepared by arc melting using ZrB 2 and β-SiC powders as raw materials and their Vickers micro-hardness, electrical conductivity and thermal conductivity were investigated. The eutectic composition of the ZrB 2 -SiC system was ZrB 2 -58.5 mol%SiC with a labyrinthine microstructure 100 nm in width and several μm in length. The hardness of the ZrB 2 -SiC composites increased with increasing SiC content and showed the highest value of 24 GPa at an indenter load of 4.9 N around the eutectic composition. The ZrB 2 -SiC eutectic composite had the highest fracture hardness of 6 MPa m 1/2 . The electrical conductivity of ZrB 2 -SiC composites ranged from 3.2×10 4 to 5.0×10 6 S m -1 at room temperature and decreased with increasing temperature. Their thermal conductivity at room temperature was 70 to 95 W m -1 K -1 and decreased with increasing temperature. The eutectic composite had the lowest thermal conductivity.