Effects of the electric field on microstructure and electrical properties of ZnO–Bi2O3–Co2O3 varistor by flash sintering.

The dense bulk ZnO–Bi₂O₃–Co₂O₃ varistor ceramics were obtained via flash sintering. The effect of electric field on densification, microstructure, and electrical properties of ZnO–Bi₂O₃-based varistor ceramics, which were under different electric fields by a constant heating flash sintering process was investigated. The results showed that when the electric field was increased from 200 to 350 V/cm, the onset temperature of flash sintering decreased significantly, and the peak power consumption increased. The flash-sintered specimen under the electric field of 200 V/cm at a furnace temperature of 762 °C obtained the highest nonlinear coefficient of 41.1 and the lowest leakage current of 1.57 μA. [ABSTRACT FROM AUTHOR]