Influence of Sintering Temperature on the Electrical Properties of (La, Ta)-Doped TiO2 Capacitor-Varistor Ceramics
An investigation was made of low voltage TiO2 varistors doped with Ta2O5 and La2O3. TiO2 ceramics doped with 0.7 mol% La2O3 and 0.1 mol% Ta2O5 were sintered at different temperature ranging from 1350 to 1450°С . The influence of sintering temperature on microstructure and nonlinear properties of the (La, Ta)-doped TiO2 ceramics was studied. The varistor of 99.2 mol%-0.7 mol%La2O3-0.1 mol% Ta2O5 composite sintered at 1380°С has a maximal nonlinear coefficient of α =5.2 and a low breakdown voltage of 7.6 V/mm, which is consistent with its highest grain-boundary barriers. According to these results, it is suggested that the sample sintered at 1380°С forms the most efficient boundary barrier layer. Therefore, the sintering temperature is a very important varible which should not be despised in the project of TiO2 based varistors production.
Huaiying Zhou, Tianlong Gu, Daoguo Yang, Zhengyi Jiang, Jianmin Zeng
Q. Qin et al., "Influence of Sintering Temperature on the Electrical Properties of (La, Ta)-Doped TiO2 Capacitor-Varistor Ceramics", Advanced Materials Research, Vols. 197-198, pp. 294-297, 2011