SrTiO3/CaCu3Ti4O12复合陶瓷材料的介电性能

摘要

本文采用固相反应法制备了xSrTiO3/(1-x)CaCu3 Ti4O12 (x=0,0.2,0.4,0.6,0.8,1)复合陶瓷,研究了复合材料的物相、微观结构和宽温度宽频率范围内的介电性能.结果表明:在1348～1600 K的温度范围内烧结能够得到致密性良好的xSrTiO3/(1-x)CaCu3 Ti4O12 (x=0,0.2,0.4,0.6,0.8,1)复合陶瓷.频率为100 kHz时,样品的室温介电常数随SrTiO3含量的增加而减少,从71358 (x=0)单调减少至270(x=1),其变化规律遵循Lichtenecker法则.介电损耗随SrTiO3含量的增加先增大后减少.当x=0.2时,样品与CaCu3 Ti4O12陶瓷的介电性能相似,存在低温的介电弛豫和巨介电常数平台.随着SrTiO3含量的增加,复合陶瓷的低温介电弛豫激活能增大,介电响应被抑制,而高温介电响应由于高温电导的影响而增强,使得CaCu3 Ti4 O12特有的巨介电常数平台随着SrTiO3的增加逐渐消失,xSrTiO3/(1-x)CaCu3 Ti4 O12复合材料的温度依赖性增强.%xSrTiO3/(1-x)CaCu3Ti4O12 (x=0,0.2,0.4,0.6,0.8,1) composites were prepared by solid-state reaction process.The phase structure,microstructure,dielectric properties of the composites were investigated.The results exhibit that the dense composites can be sintered at the temperature range from 1348 to 1600 K.The dielectric constant of the samples decreases from 71358 (x=0) to 270 (x=0) with increasing content of SrTiO3 at room temperature and 100 kHz,which follows Lichtenecker's logarithmic law of composites.The dielectric loss first increased and then suppressed with the SrTiO3 increase.The dielectric properties of 0.2SrTiO3/0.8CaCu3Ti4O12 composites are quite similar to CaCu3Ti4O12 ceramics with the lowtemperature dielectric relaxation and giant dielectric constant step.With increasing content of SrTiO3,the lowtemperature dielectric relaxation is depressed and the high-temperature dielectric relaxation is enhanced.The former may be due to the increase of activation energy for low-temperature dielectric relaxation,while the latter by the effect of high temperature conductivity.Therefore,the distinctive giant dielectric constant steps of CaCu3 Ti4O12 ceramics are wearing off with increasing SrTiO3 content.The temperature dependences of SrTiO3 /CaCu3Ti4O12 composites are thus enhanced.