(Ge, GeO2, Ta2O5, BaCO3) co-doping TiO2 varistor ceramics

作者：Kang, Kunyong; Yan, Jikang; Zhang, Jiamin; Du, Jinghong; Yi, Jianhong; Liu, Yichun; Bao, Rui; Tan, Songlin; Gan, Guoyou^*

来源：Journal of Alloys and Compounds, 2015, 649: 1280-1290.

DOI：10.1016/j.jallcom.2015.05.112

• TiO2 varistor
• Co-doping
• Nonlinear coefficient
• Ge and GeO2

The present study investigated the effect of co-doping with elemental crystal Ge or/and GeO2 on the TiO2-Ta2O5-BaCO3 varistor ceramic. Results showed that with the doping content of Ta2O5 and BaCO3 of 0.3 mol% and 0.2 mol%, respectively, the optimum doping content of 0.4 mol% Ge and 1.2 mol% GeO2 exhibited the highest alpha value (alpha = 12.1), lower breakdown voltage E-B (E-B = 20.8 V mm(-1)), lesser leakage current J(L) (J(L) = 11.5 mu A cm(-2)), and highest grain boundary barrier phi(B) (phi(B) = 0.93 eV). The microstructural analyses indicated that Ge-G-O-2 co-doping notably changed the TiO2-Ta2O5-BaCO3 ceramic microstructure, increased alpha, and decreased EB. In addition, Ge and GeO2, which function as sintering aids, reduced the sintering temperature caused by the low melting point; the best sintering temperature was 1280 degrees C for TiO2-Ta2O5-BaCO3-Ge-G-O-2 ceramic.

• 出版日期2015-11-15
• 单位昆明理工大学