高居里点(1-x)Ba_(0.998)La_(0.002)TiO_3+xBi_4Ti_3O_(12)系统陶瓷微观结构及温度特性的研究

Investigation on Microstructure and Resistivity-temperature Properties of (1-x)Ba_(0.998)La_(0.002)TiO_3 +xBi_4Ti_3O_(12) System Ceramics with High Curie Temperature

采用传统陶瓷制备工艺制备(1-x)Ba0.998La0.002TiO3+xBi4Ti3O12(0≤x≤0.01)系统陶瓷。对在还原气氛(氮气)中烧成的陶瓷样品在一定温度下进行再氧化处理。研究了不同Bi4Ti3O12掺杂浓度以及再氧化过程对BaTiO3微观结构、介电性能及居里温度Tc的影响。结果表明:掺杂Bi4Ti3O12后,BaTiO3陶瓷的晶粒尺寸明显减小;Bi4Ti3O12具有提高陶瓷居里点温度的作用,当x=1.0时,居里温度提高到Tc=150℃。随着BIT加入量的增加,电子与缺位混合补偿,晶格中将产生金属离子缺位,以补偿多余电子,因此随着BIT掺入量的增加,电阻率逐渐增大。

（1-x） Ba0.998La0.002TiO3＋xBi4Ti3O12 （0≤x≤0.01） system ceramics were prepared by solid-state reaction technology. The samples were sintered in reducing atmosphere （nitrogen） and then reoxidized. The microstructure of samples were characterized by SEM,electrical properties were analyzed by the resistivity-temperature testing apparatus and capacitance testing selector. The results showed that the grain size of BaTiO3 ceramics significantly decreased after doping Bi4Ti3O12; Curie temperature of ceramics increased （Tc= 150 ℃）. As the addition of the amount of BIT increasing,the electron and vacancies compensated each other,extra electrons were compensated with lattice metal ions vacancy,thus resistivity gradually increased.