CaCu_3Ti_4O_(12)-MgTiO_3陶瓷的介电性能与I-V非线性特征

Dielectric properties and nonlinear current-voltage behavior of MgTiO_3-doped CaCu_3Ti_4O_(12) ceramics

采用固相反应法制备了一系列CaCu3Ti4O12-xMgTiO3(x=0,0.25,0.5,1.0)复相陶瓷,研究了MgTiO3掺杂对CaCu3Ti4O12(CCTO)陶瓷相结构、显微组织、介电性能和I-V非线性特征的影响.研究发现:MgTiO3掺杂不仅使CCTO低频介电损耗降低,压敏电压提高,而且使I-V非线性系数显著增大.电学性能的改善与由MgTiO3掺杂后导致晶粒尺寸均匀化,晶界厚度减薄且绝缘性提高有关.其中,CaCu3Ti4O12-0.5MgTiO3陶瓷具有良好的综合电学性能:εr=53958,tanδ=0.06(1kHz),压敏电压Eb=295V/mm且非线性系数α=66.3.

The CaCu3Ti4O12-xMgTiO3（x = 0,0. 25,0. 5,1. 0） ceramics have been prepared by a solid-state reaction method. The effects of MgTiO3 doping on the phase structure,microstructure and dielectric properties of CaCu3Ti4O12 ceramics have been investigated. The results indicate that MgTiO3 doping not only reduced the dielectric loss of low frequency range and raised the breakdown voltage but also significantly improved the I-V nonlinearity coefficient. The optimized properties of MgTiO3 doped CaCu3Ti4O12 can be well explained by the uniformity of the grains,the reduction of the average grain boundary thinkness and the enhancement of the grain boundary resistance. Among the CaCu3Ti4O12-MgTiO3 specimens in this work,the CaCu3Ti4O12-0. 5MgTiO3 specimen has achieved the best comprehensive properties,which include a dielectric constant （εr） of 53958,dielectric loss （tanδ） of 0. 06 at 1 kHz,breakdown voltage （Eb） of 295 V /mm and a large nonlinearity coefficient of 66. 3.