Microstructure and properties of ZnO-Bi₂O₃-based varistor ceramics via flash sintering

Abstract

Purpose

This paper aims to study the effects of MnO₂ on the ZnO–Bi₂O₃-based varistor prepared via flash sintering (FS)

Design/methodology/approach

MnO₂-doped ZnO–Bi₂O₃-based varistors were successfully prepared by the FS with a step-wise increase of the .current in 60 s at the furnace temperature <750°C under the direct current electric field of 300 V cm⁻¹. The FS process, microstructure and the electrical performance of ZnO–Bi₂O₃-based varistors were systematically investigated.

Findings

The doping of MnO₂ significantly decreased the onset temperature of FS and improved the electrical performance of FS ZnO varistor ceramic. The sample with 0.5 mol% MnO₂ doping shows the highest improvement, with the nonlinear coefficient of 18, the leakage current of 16.82 µA, the threshold voltage of 459 V/mm and the dielectric constant of 1,221 at 1 kHz.

Originality/value

FS is a wonderful technology to enhance ZnO varistors for its low energy consumption, and a short sintering time can reduce grain growth and inhabit Bi₂O₃ volatilize, yet few research studies work on that. In this research, the authors analyzed the FS process and improved the electrical characteristics through MnO₂ doping.

Citation

Jiang, M., Shi, M., Li, J., Liu, J., Zhang, L., Qin, J., Jiu, Y., Tang, B. and Xu, D. (2022), "Microstructure and properties of ZnO-Bi₂O₃-based varistor ceramics via flash sintering", Microelectronics International, Vol. 39 No. 4, pp. 166-174. https://doi.org/10.1108/MI-05-2022-0079