The Role of Niobium in (Ca, Si, Ce, Nb)-Doped TiO2 Varistors
The present work attempted to investigate the effect of Nb addition on the electrical properties of the (Ca,Si,Ce,Nb)-doped TiO2 ceramics. The content of added niobium is in the range 0.1-1.0mol %, while that of the other additives keeps constant. The results showed that an optimal composition doped with 0.8mol% Nb2O5, followed by sintering at 1350°C, was obtained with low V1 mA of 7.22V, high nonlinear coefficient of 5.76, ultrahigh dielectric constant (er = 86000) as well as relatively low loss (tgd = 0.52) in room temperature at 1 kHz. SEM studies show that change of niobium had significant influence on grain growth and micro structural characteristics of the sintered samples.
Wei Pan, Jianghong Gong, Chang-Chun Ge and Jing-Feng Li
S. H. Luo et al., "The Role of Niobium in (Ca, Si, Ce, Nb)-Doped TiO2 Varistors", Key Engineering Materials, Vols. 280-283, pp. 297-300, 2005