Preparation of TiC-TiB2-SiC ternary eutectic composites by arc-melting and their characterizations

Abstract

TiC-TiB2-SiC composites were synthesized by arc-melting using TiC, TiB2 and SiC powders as starting materials in Ar atmosphere. TiC-TiB2-SiC system was a ternary eutectic, whose eutectic composition was 34TiC-22TiB2-44SiC (mol%). The TiC-TiB 2-SiC eutectic composite showed a lamellar texture, where lamellar SiC grains paralleled to lamellar TiC grains. TiB2 grains had an angle of about 30 to 60° with lamellar SiC and TiC grains. The hardness of TiC-TiB2-SiC eutectic composite was 25.5 GPa at the load of 1.96 N and increased with increasing TiC content. The electrical conductivity of the eutectic composite was 2.81 × 103 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-TiB2-SiC ternary composites decreased with increasing SiC content, and the thermal conductivity decreased with increasing TiC content. © 2006 The Japan Institute of Metals.