Effect of TiC addition on microstructure and properties of network structured TiC–ZrO2 composite conductive ceramics

Zirconia (ZrO2) ceramics have excellent mechanical properties and high-temperature conductivities. However, ZrO2 ceramics do not possess room-temperature conductivity, which significantly limits their application as functional components in smart communication devices and wearable smart products. To achieve room-temperature conductivity in ZrO2 ceramics, this study prepared a network-structured TiC–ZrO2 composite conductive ceramic with a low titanium carbide (TiC) addition using pressureless sintering. The influence of the TiC addition on the microstructure, mechanical properties, and electrical properties of the TiC–ZrO2 composite material was investigated. The results showed that the composite material consists of cubic zirconia (c-ZrO2), tetragonal zirconia (t-ZrO2), and titanium carbide (TiC) phases. When the TiC content was 11 vol %, the relative density, open porosity, flexural strength, and fracture toughness of the sample were 98.6 ± 0.1 %, 0.16 ± 0.06 %, 383 ± 38 MPa, and 4.66 ± 0.26 MPa m1/2, respectively. The electrical percolation threshold of the TiC–ZrO2 composite was between 8.0 and 11.0 vol %. When the TiC content is 18.8 vol %, the sample exhibited the lowest room-temperature resistivity of 3.00 × 10−5 Ω m. The electrical resistance of the TiC–ZrO2 composite material is mainly attributed to the grain boundary effect. With increasing TiC content, the resistivity of the composite material decreased, exhibiting linear conductivity and achieving conductive percolation characteristics.