Influence of leakage current density on the stability of Sb2O3 doped ZnO-V2O5-Bi2O3-MnO2 based varistor ceramics during the DC and thermal stress

Abstract

This study investigated the influence of DC-thermal stress on the stability of Sb2O3 doped ZnO–V2O5–Bi2O3–MnO2 based varistor ceramics from 0 to 1 mol%. The materials were processed using a conventional solid-state technique. The samples were characterized using XRD, SEM, and EDX techniques. The use of XRD and EDX analyses related to those cited in the literature confirmed the presence of Zn7Sb2O12, MnVO4, BiVO4, and Zn3(VO4)2 polymorphs as the secondary phase including ZnO hexagonal wurtzite structure and MnO2 as a primary phase. The EDX analyses reveal the presence of the Zn7Sb2O12 spinel phase located at the triple point junctions, nodal point, and embedded in ZnO bulk grains. Henceforth, the results showed that Sb2O3 dopingcan improve the stability of the varistor ceramics, particularly in the phase formation of Zn7Sb2O12. This contributed to good stability of Sb2O3 doped ZVBM varistor ceramics in terms of degradation rate coefficient of 2.02x10-7 mA h1/2 which was accompanied by low leakage current density around -67%, largest barrier height of 1.54%, breakdown field of 69.83% and ? around 72.94%