Grain-growth-induced high electrical conductivity in SiC-BN composites

SiC-BN composites were fabricated by conventional hot-pressing from β-SiC and h-BN nanopowders with 2 vol% yttria as a sintering additive. Electrical and thermal properties of the composites were investigated as a function of initial BN content. Owing to the nanosize of the starting powders, the grain-growth-assisted N-doping of the SiC lattice was significantly enhanced during liquid-phase sintering, yielding the highest-reported electrical conductivity of ~124 (Ω cm)−1 for a SiC-4-vol% BN composite. The typical values of electrical resistivity and thermal conductivity of the SiC-4-vol% BN composite at room temperature were 8.1 × 10−3 Ω cm and 92.4 W m−1 K−1, respectively.