Flash Assisted Synthesis and Electrical Performance of MnO2-doped ZnO-Bi2O3-based Ceramics

Abstract

How to prepare high-performance ZnO-based varistor ceramics in a short time and at a low temperature remains a key challenge. Flash sintering method provides an effective approach to solve this challenge. Here, MnO2-doped ZnO-Bi2O3-based dense varistor composite ceramics were successfully prepared by the flash sintering method at the furnace temperature < 750 ℃ in 60 s under the DC electric field of 300 V⋅cm− 1. The effects of MnO2 on the onset of furnace temperature, specimen temperature, and specimen conductivity were systematically investigated in the flash sintering process. The results of flash sintering show that the onset of furnace temperature of ZnO-Bi2O3-based composite ceramic containing 0.5 mol% MnO2 is only 704 ℃, which is significantly lower than that of undoped ZnO-Bi2O3-based varistor ceramic. The measurement results of the electrical properties for all flash-sintered composite varistors ceramics show that the composite sample containing 0.5 mol% MnO2 has the best electrical performance parameters compared with the undoped ZnO-Bi2O3-based varistor ceramic. The flash-sintered ceramic containing 0.5 mol% MnO2 obtained the nonlinear coefficient of 18, the leakage current of 16.82 µA, and the dielectric constant of 1221 at 1 kHz.