Ge掺杂对TiO2-Nb2O5-CaCO3压敏陶瓷结构及性能的影响

TiO₂ 压敏电阻是一种典型的非线性电流-电压电子器件, 本文研究了Ge掺杂对TiO₂-Nb₂O₅-CaCO₃压敏陶瓷的非线性系数α和压敏电压E_B的影响。采用传统的球磨-成型-烧结方法成功制备Ge掺杂TiO₂-Nb₂O₅-CaCO₃压敏陶瓷, 用压敏直流参数仪测试样品的非线性系数α、压敏电压E_B和漏电流J_L等电学性质, 并根据相关公式计算样品平均势垒高度。XRD、XPS、SEM和STEM分析表明, Ge掺杂显著改变TiO₂-Nb₂O₅ -CaCO₃压敏陶瓷微结构, 提高非线性系数α和减小压敏电压E_B。当施主Nb₂O₅和受主CaCO₃掺杂浓度分别为0.5mol%时, 掺杂1.0mol% Ge的压敏陶瓷获得了最高的非线性系数和较低的压敏电压(α=10.6, E_B=8.7 V/mm), 明显优于不掺杂Ge的TiO₂-Nb₂O₅-CaCO₃压敏陶瓷。此外, Ge熔点较低, 作为烧结助剂可以降低陶瓷的烧结温度, TiO₂-Nb₂O₅-CaCO₃-Ge压敏陶瓷最佳烧结温度是1300℃。

Ge-doping in TiO2-Nb2O5-CaCO3 Varistor Ceramics: Structure and Property

TiO₂ varistors are typical electronic devices with nonlinear current-voltage property fabricated from TiO₂ ceramics. This study investigated the influence of Ge doping on the nonlinear coefficient α and the breakdown electric field E_B of TiO₂-Nb₂O₅-CaCO₃ varistor ceramics. TiO₂-Nb₂O₅-CaCO₃ varistor ceramics doped with Ge were successfully prepared by using traditional method of ball milling-molding-sintering. The electrical performance, including nonlinear coefficient α, breakdown electric field E_B, and leakage current J_L, was tested with a varistor-direct current-parameter instrument. Average barrier height Φ_B of each sample was calculated by relevant formula. Analysis of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and scanning transmission electronic microscopy demonstrated that Ge doping notably changed the microstructure of TiO₂-Nb₂O₅-CaCO₃ ceramics, thereby increasing α and decreasing E_B. When Nb₂O₅ and CaCO₃ doping content were 0.5mol%, the TiO₂-Nb₂O₅-CaCO₃ varistor ceramics doping with 1.0 mol% Ge exhibited high α (10.6), low E_B (8.7 V/mm), and highest Φ_B (1.73 eV), superior to previous published findings. Furthermore, Ge with low melting point as sintering aid could reduce the sintering temperature of the varistor ceramics, with optimal sintering temperature at 1300℃.