Effect of La2O3 on the Microstructure and Electrical Properties of (Ti,Sn)O2 Varistor Ceramics
(Ti,Sn)O2 varistors doped with different amount of La2O3 were obtained by ceramic sintering processing at 1250 . The effect of La2O3 on the microstructure and nonlinear electrical behavior of the (Ti,Sn)O2 ceramics were investigated. The ceramics have nonlinear coefficients of α=6.2–8.5. Experimental evidence shows that small quantities of La2O3 improve the nonlinear properties of the samples significantly. It was found that an optimal doping composition of 1.0mol% La2O3 leads to a low breakdown voltage of 18.1V/mm, a high nonlinear coefficient of 8.5, which is consistent with the highest and narrowest grain boundary barriers of the ceramics.In view of these electrical characteristics, the (Ti,Sn)O2 varistors with 1.0mol% La2O3 ceramic is a viable candidate for low voltage varistor devices. The characteristics of the ceramics can be explained by the effect of the substitution of La3+ for Ti4+ or Sn4+.
Zhengyi Jiang, Jingtao Han and Xianghua Liu
M. H. Wang et al., "Effect of La2O3 on the Microstructure and Electrical Properties of (Ti,Sn)O2 Varistor Ceramics", Advanced Materials Research, Vols. 152-153, pp. 1391-1394, 2011