Electrically conductive SiC ceramics processed by pressureless sintering

Abstract Polycrystalline SiC ceramics with 10 vol% Y ₂ O ₃ ‐AlN additives were sintered without any applied pressure at temperatures of 1900‐2050°C in nitrogen. The electrical resistivity of the resulting SiC ceramics decreased from 6.5 × 10 ¹ to 1.9 × 10 ⁻² Ω·cm as the sintering temperature increased from 1900 to 2050°C. The average grain size increased from 0.68 to 2.34 μm with increase in sintering temperature. A decrease in the electrical resistivity with increasing sintering temperature was attributed to the grain‐growth‐induced N‐doping in the SiC grains, which is supported by the enhanced carrier density. The electrical conductivity of the SiC ceramic sintered at 2050°C was ~53 Ω ⁻¹ ·cm ⁻¹ at room temperature. This ceramic achieved the highest electrical conductivity among pressureless liquid‐phase sintered SiC ceramics.