CeO_2掺杂对BaTiO_3基陶瓷电介质的影响

Effects of CeO_2 Dopants on Properties of BaTiO_3 Based Capacitor Ceramics

研究采用固相法在BaTiO3中掺杂不同含量的CeO2对体系介电性能及微观结构的影响,讨论了不同烧结温度下体系介电性能的变化。研究发现,当组成为Ba(Ce0.08Ti0.92)O3时,试样在1 490℃保温2 h中可获得性能优良的电容器介质材料。体系的相对介电系数可达5 300,介质损耗仅为2.42%,绝缘电阻率为1.39×107Ω.cm,居里温度向室温方向移动至45℃。与此同时,借助扫描电镜对烧结体进行了微观形貌分析。结果表明,CeO2掺杂使Ce4+部分取代Ti4+,有效地增加了体系的相对介电系数,降低了介质损耗,并起到了良好的居里峰展宽及移峰效应。此外,CeO2掺杂亦可抑制晶粒的异常长大,得到较高致密度的烧结体。

The effects of CeO2 on dielectric properties of BaTiO3 based ceramics prepared by traditional solid state method were investigated. The variation of dielectric properties at different sintering temperature was also discussed. It＇s found that the samples of Ba（Ce0.08Ti0.92 ）O3 with excellent electric properties could be obtained by sintering at 1 490℃ for 2 hours, showing high relative dielectric constant up to 5 300, low dielectric loss 2.42~~ and high insulation resistivity 1.39 × 10^7Ω· cm. The Curie temperature of the samples was shifted to 45℃ The mor- phology analysis of sintered samples was conducted by SEM. It can be concluded that CeO2 dopant improves the relative dielectric constant effectively, reduces the dielectric loss dramatically and moves the Curie temperature to lower value due to the part substitution of Ce^4＋ for Ti^4＋ . The adulteration of CeO2 can also restrain the unwanted growth of the grains so as to produce denser sintered samples.