Electrical and Thermal Properties of <scp> <scp>SiC</scp> </scp> Ceramics Sintered with Yttria and Nitrides

Abstract

The electrical and thermal properties of SiC ceramics containing 1 vol% nitrides ( BN , AlN or TiN ) were investigated with 2 vol% Y 2 O 3 addition as a sintering additive. The AlN ‐added SiC specimen exhibited an electrical resistivity (3.8 × 10 1 Ω·cm) that is larger by a factor of ~10 2 compared to that (1.3 × 10 −1 Ω·cm) of a baseline specimen sintered with Y 2 O 3 only. On the other hand, BN ‐ or TiN ‐added SiC specimens exhibited resistivity that is lower than that of the baseline specimen by a factor of 10 −1 . The addition of 1 vol% BN or AlN led to a decrease in the thermal conductivity of SiC from 178 W/m·K (baseline) to 99 W/m·K or 133 W/m·K, respectively. The electrical resistivity and thermal conductivity of the TiN ‐added SiC specimen were 1.6 × 10 −2 Ω·cm and 211 W/m·K at room temperature, respectively. The present results suggest that the electrical and thermal properties of SiC ceramics are controllable by adding a small amount of nitrides.