Electrical properties and microstructural evolution of ZrO2–Al2O3–TiN nanocomposites prepared by spark plasma sintering

Electroconductive ZrO2–Al2O3–25 vol% TiN ceramic nanocomposites were prepared by spark plasma sintering at 1200 °C for 3 min. The electrical resistivity of the composites decreased from 4.5 × 10−4 Ω m to 3 × 10−5 Ω m as the Al2O3 content in the ZrO2–Al2O3 matrix increased from 0 to 100 vol%. SEM images graphically presented the microstructural evolution of the composites and a geometrical percolation model was applied to investigate the relationship between the electrical property and the microstructure. The results indicated that the addition of Al2O3 to ZrO2–TiN improved the electrical conductivity of the material by tailoring the structure from “nano–nano” type for ZrO2–TiN to “micro–nano” type for ZrO2–Al2O3–TiN.