The SnO2‐based varistor is a kind of new varistor ceramic material with high nonlinear electrical properties and high thermal conductivity. To improve the comprehensive performance, we focus on how to lower the residual voltage ratio of SnO2‐based varistor. In this article, the influence of Cr2O3 on the microstructure, nonlinear J–E characteristics and surge current performances have been investigated. By changing mean grain size and bringing oxygen vacancies, different Cr2O3 concentrations make the residual voltage ratio increase or decrease accordingly. The lowest residual voltage ratio we obtained is 1.68, when the content of Cr2O3 is 0.03 mol%, which is comparative to commercial ZnO‐based varistor of the same specifications and close to practical use.

SnO 2 -based varistor samples doped with Co 2 O 3 , Nb 2 O 5 and Cr 2 O 3 were prepared by ball-mixed oxide method. The microstructure, nonlinear I-V characteristic and surge current performances of these samples were investigated. This paper mainly focused on the dependence of the residual voltage ratio behavior of SnO 2 -based varistors on Nb 2 O 5 addition, different factors influencing the residual voltage ratio in different concentration of Nb 2 O 5 were analyzed. The Nb 2 O 5 addition influences its residual voltage ratio by changing the grain size, forming defects (especially the free electrons) and cumulative effect. The measured results indicated that the optimally obtained sample with 0.07mol% Nb 2 O 5 possesses the lowest residual voltage ratio of 1.86, the corresponding nonlinear coefficient and the threshold electric field are 42.6 and 364.6 V/mm, respectively. SnO 2 -based varistor, Nb 2 O 5 , residual voltage ratio Citation:Wei Q Y, He J L, Hu J. Dependence of residual voltage ratio behavior of SnO 2 -based varistors on Nb 2 O 5 addition .

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