La_2O_3掺杂对TiO_2系压敏陶瓷结构和性能的影响

采用传统的固相法制备了La2O3掺杂的TiO2系压敏陶瓷,通过XRD和SEM分析,测试其结构及压敏性能、介电常数和晶界势垒特性。结果表明:La2O3掺杂对所获陶瓷的结构和性能有显著的影响,在1380℃烧结条件下,掺杂x(La2O3)为0.70%的陶瓷表现出优良的综合电性能,其压敏电压为7.6V/mm,非线性系数为5.2,相对介电常数εr为9.96×104,介电损耗tanδ为0.32,这与该陶瓷具有最高的晶界势垒高度相一致。

Effect of La203 doping on the structure and properties of TiO2 system varistor ceramics

The La2O3-doped TiO2 system varistor ceramics were prepared by the conventional solid reaction method. The microstructure was analyzed with XRD and SEM. The electrical properties were studied by V-I curves, dielectric and boundary defect barriers measurements. The results show that the La2O3 doping has significant effect on the varistor properties and dielectric properties of obtained TiO2 system varistor ceramics sintering at 1 380 ℃. It is found that an optimal doped amount of 0.70% (mole fraction) of La2O3 leads to a low breakdown voltage of 7.6 V/mm, a nonlinear coefficient of 5.2, an ultrahigh relative permittivity of 9.96×104 and a relatively low loss of 0.32, which is consistent with the highest grain-boundary defect barriers.