No abstract

TiC-TiB 2 -SiC composites were synthesized by arc-melting using TiC, TiB 2 and SiC powders as starting materials in Ar atmosphere. TiCTiB 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 1.96 N and increased with increasing TiC content. The electrical conductivity of the eutectic composite was 2:81 Â 10 3 Sm À1 at the room temperature and decreased with increasing temperature. The thermal conductivity of the eutectic composite was 25 to 60 WK À1 m À1 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.

TiB 2 -SiC system composites were prepared using TiB 2 and SiC powders as starting materials by an arc-melted method in Ar atmosphere. The TiB 2 -SiC system was binary eutectic. The eutectic composition was 40TiB 2 -60SiC (mol%) showing a labyrinth texture. The hardness of the eutectic composite was 27 to 30 GPa at the loads from 0.98 to 9.8 N. The electrical conductivity of the composites increased with increasing the content of TiB 2 . The electrical conductivity of the eutectic composite slightly decreased from 6.5 to 6:1 Â 10 5 Sm À1 with increasing temperature from 298 to 1200 K. The thermal conductivity of the composites increased with increasing the content of SiC. The thermal conductivity of the eutectic composite decreased from 70 to 45 WK À1 m À1 with increasing temperature.