微量La取代对（Ba0.9Ca0.1）（Ti0.8Zr0.2）O3陶瓷介电性能的影响

摘要

(Ba0.9Ca0.1)1–xLax(Ti0.8Zr0.2)O3(0≤x≤0.005) lead-free ceramics were prepared by conventional solid-state method. The effects of La3+ substitution on the microstructure and dielectric properties of (Ba0.9Ca0.1)(Ti0.8Zr0.2)O3 were studied. The results show that La3+ ion diffuses into the BCZT lattice and the grain growth is inhibited by La2O3substitution. The Curie temperature shifts to lower temperature with the increases of La3+concentration and the dielectric constant at room temperature increases firstly then decreases with further addition while the dielectric loss shows the reverse change trend. The frequency stability of dielectric constant is improved after La3+ substitution. The optimum dielectric property is obtained by (Ba0.9Ca0.1)0.997La0.003(Ti0.8Zr0.2)O3, with the dielectric constant of 18 592 at 1 kHz at room temperature, the dielectric loss of only 0.013, and the Curie temperature of 281 K.%采用传统固相法制备了(Ba0.9Ca0.1)1–xLax(Ti0.8Zr0.2)O3(0≤x≤0.005)系列无铅陶瓷，并研究了微量La取代对锆钛酸钡钙陶瓷微观结构及介电性能的影响。X射线衍射和扫描电镜结果表明，La3+进入锆钛酸钡钙晶格中形成均一的固溶体，并能有效抑制陶瓷颗粒的增长。介电性能测试结果显示，随着La3+含量的增加，居里温度降低，室温介电常数先增大后减小，介电损耗则相反的趋势，取代后的样品介电频率稳定性增强。样品(Ba0.9Ca0.1)0.997La0.003(Ti0.8Zr0.2)O3的综合介电性能最佳，在频率为1 kHz时，室温介电常数可达18592，而相应的介电损耗仅为0.013，居里温度为281 K。