Microstructural, electrical, and mechanical properties of conductive SiC ceramics fabricated by spark plasma sintering

Nitrogen (N)‐doped conductive silicon carbide (SiC) of various electrical resistivity grades can satisfy diverse requirements in engineering applications. To understand the mechanisms that determine the electrical resistivity of N‐doped conductive SiC ceramics during the fast spark plasma sintering (SPS) process, SiC ceramics were synthesized using SPS in an N2 atmosphere with SiC powder and traditional Al2O3–Y2O3 additive as raw materials at a sintering temperature of 1850–2000°C for 1–10 min. The electrical resistivity was successfully varied over a wide range of 10−3–101 Ω cm by modifying the sintering conditions. The SPS‐SiC ceramics consisted of mainly Y–Al–Si–O–C–N glass phase and N‐doped SiC. The Y–Al–Si–O–C–N glass phase decomposed to an Si‐rich phase and N‐doped YxSiyCz at 2000°C. The Vickers hardness, elastic modulus, and fracture toughness of the SPS‐SiC ceramics varied within the ranges of 14.35–25.12 GPa, 310.97–400.12 GPa, and 2.46–5.39 MPa m1/2, respectively. The electrical resistivity of the obtained SPS‐SiC ceramics was primarily determined by their carrier mobility.