Preparation of TiC-TiB<SUB>2</SUB>-SiC Ternary Eutectic Composites by Arc-Melting and Their Characterizations

Abstract

TiC-TiB 2 -SiC composites were synthesized by arc-melting using TiC, TiB 2 and SiC powders as starting materials in Ar atmosphere. TiC-TiB 2 -SiC system was a ternary eutectic, whose eutectic composition was 34TiC-22TiB 2 -44SiC (mol%). The TiC-TiB 2 -SiC eutectic composite showed a lamellar texture, where lamellar SiC grains paralleled to lamellar TiC grains. TiB 2 grains had an angle of about 30 to 60° with lamellar SiC and TiC grains. The hardness of TiC-TiB 2 -SiC eutectic composite was 25.5 GPa at the load of 1.96N and increased with increasing TiC content. The electrical conductivity of the eutectic composite was 2.81 x 10 3 Sm -1 at the room temperature and decreased with increasing temperature. The thermal conductivity of the eutectic composite was 25 to 60 WK -1 m -1 at the room temperature and decreased with increasing temperature. The electrical conductivity of TiC-TiB 2 -SiC ternary composites decreased with increasing SiC content, and the thermal conductivity decreased with increasing TiC content.