Two-step method fabricating high nonlinearity ZnVSb based varistors

A two-step method was introduced to fabricate ZnO–V2O5–Sb2O3 (ZnVSb) based varistor at low temperatures, such as 900–950 °C. Sb2O3/V2O5 (V/Sb) precursor was first synthesized and then used to replace Sb2O3 as one of the main dopants. The effect of its concentration on the microstructure and electrical properties of the ZnVSb based ceramic was investigated at doping levels up to 1.5 mol%. The microstructural homogeneity of the ceramic was greatly improved by the addition of the precursor. With increasing V/Sb precursor, the average grain size decreased, while the nonlinearity of the as sintered ceramic was enhanced (αMax = 89). The ZnVSb ceramic is a promising material in the fabrication of multi-layered varistor, in which it could be co-sintered with pure Ag inner electrode.