钛酸铋钠系陶瓷固溶改性及介电弛豫性能

Modification and Dielectric Relaxation of Sodium Bismuth Titanate Ceramics

采用电子陶瓷合成工艺制备了致密的钛酸铋钠基固溶陶瓷(1–x)(Na_(0.5)Bi_(0.5))TiO_3–xLa(Zn_(0.5)Ti_(0.5))O_3,研究了该系陶瓷的相组成、微观形貌及介电性能。结果表明:在(Na_(0.5)Bi_(0.5))TiO_3中引入La(Zn_(0.5)Ti_(0.5))O_3后形成了单相钙钛矿固溶体;随着La(Zn_(0.5)Ti_(0.5))O_3引入量的增加,晶粒形貌由球状向立方体状转变,晶棱显著锐化,晶粒细化,尺寸更加均匀;La(Zn_(0.5)Ti_(0.5))O_3的引入使得(Na_(0.5)Bi_(0.5))TiO_3晶体中氧空位增多以及A、B位离子种类增多,晶体结构中离子分布无序化程度加剧,致使该系陶瓷的介电频率色散显著,介电弛豫激活能降低(从1.7 e V降低至1.32 e V),弛豫性增强。

The dense sodium bismuth titanate-based solid solution ceramics of （1-x）（Na0.5Bi0.5）TiO3-xLa（Zn0.5Ti0.5）O3 were fabricated via an electronic ceramic synthesis technique. The phase structure, microstructure and dielectric property of the ceramics were investigated. The results indicate that the sodium bismuth titanate has a perovskite structure after adding a certain amount of La（Zn0.5Ti0.5）O3. The grain morphology changes from sphere to cube-like as the content of La（Zn0.5Ti0.5）O3 increases. The size of grain is small and the microstructure becomes more uniform. In addition, the dielectric frequency dispersion and relaxation enhance with increasing the content of La（Zn0.5Ti0.5）O3 due to the increased oxygen vacancy in crystal and intensified disorder degree of both A-site and B-site cations in （Na0.5Bi0.5）TiO3 perovskite lattice. The activation energy for dielectric relaxation decreases from 1.70 to 1.32 eV.