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-TiB₂-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.