Effect of TiC Content on Microstructure and Performance of TiC/ZrO₂Conductive Ceramic Composites by Pressureless Sintering

TiC/ZrO₂ conductive ceramic composites were prepared by pressureless sintering with ZrO₂, TiC, TiO₂ and phenolic resin as raw materials and combining with in-situ synthesized TiC by carbothermal reduction reaction. The effect of TiC mass fraction (25%-40%) on the relative density, microstructure, mechanical properties and conducivity of the ceramic composites were investigated. The results show that the ceramic composites consisted of TiC and t-ZrO₂ phases. With increasing TiC content, the TiC particles in ZrO₂ matrix gradually connected with each other and then formed a continuous network structure, the bending strength of the ceramic composites increased first and then decreased, the hardness decreased first and then increased, and the relative density, fracture toughness and resistivity decreased constantly. When the mass fraction of TiC was 30%, the ceramic composite had the best comprehensive properties, whose relative density, bending strength, Vickers hardness, fracture toughness and resistivity were 97.42%, 571 MPa, 12.1 GPa, 3.43 MPa·m^1/2 and 3.10×10^-5 Ω·m, respectively.