无铅Ba(Ce,Ti)O_3陶瓷的电卡效应

Electrocaloric Effect in Lead-free Ba(Ce,Ti)O_3 Ceramics

本文使用标准固相烧结法制备了Ba(Ti_(1-x)Ce_x)O_3(x=0.10,0.15,0.20)陶瓷,通过XRD分析发现这些陶瓷中除了Ba(Ti_(1-x)Ce_x)O_3主相外,还存在少量的杂相。利用Rietveld拟合的方法,获得了Ba(Ti_(1-x)Ce_x)O_3主相中的Ce/Ti实际比例。介电温谱表明这些陶瓷均存在一个明显的介电峰,且随着x的增加,峰值温度下降,介电峰宽展宽。利用不同温度下的电滞迴线,给出了不同温度和电场强度下的极化值,通过间接法获得了这些陶瓷的电卡效应。结果表明,BaTi_(0.9)Ce_(0.1)O_3的电卡效应最强,其DT值在403K和40kV/cm的电场下达到最大值,为0.48K,电卡强度为0.12×10^(-6)K·m/V。

Ba（Til-xCex）O3 （x=0.10, 0.15, 0.20） were prepared by a standard solid-state sintering process. Apart from Ba（Ti1-xCex）O3 phase, some minor impure phases existed in these ceramics. Real ratios of Ce/Ti were determined by the Rietveld method, which were critical to the Curie temperatures of these ceramics. One peak was observed on curve of the temperature-dependence of dielectric constant. With the increasing content of cerium, the peak would shift to low temperature, while the peak width would be widen. P--E loops were recorded at different temperatures, and maximum polarizations were extracted to calculate the electrocaloric effect. Results showed the best electrocaloric effect could be obtained in BaTi0.9 Ce0.103 ceramics, that is, the maximum electrocaloric temperature change of DT is 0.48K, under the electric field of 40kV/cm and at the temperature of 403K, and its electrocaloric strength is 0.12 × 10^-6K·m/V.