Sb_2O_3对富钛型钛酸锶钡基陶瓷结构及性能的影响

Effects of Sb_2O_3 on the Structure and Dielectric Properties of Ti-rich Barium Strontium Titanate Ceramics

采用传统固相法制备Sb_2O_3掺杂(Ba_(0.7_Sr_(0.3))Ti_(1.005)O_3系介电陶瓷,通过扫描电镜、X线衍射仪及LCR测试系统,研究不同含量的Sb_2O_3及烧结工艺参数对TiO_2过量的钛酸锶钡体系微观结构及介电性能的影响。结果表明,随Sb_2O_3掺杂量增大,(Ba_(0.7)Sr_(0.3))Ti_(1.005)O_3陶瓷由立方钙钛矿结构单相固溶体转变为多相化合物。在TiO_2过量的(Ba_(0.7)Sr_(0.3))Ti_(1.005)O_3陶瓷中,Sb^(3+)进入钙钛矿晶格A位。Sb_2O_3添加量较大时,(Ba_(0.7)Sr_(0.3))Ti_(1.005)O_3基陶瓷晶粒异常长大,粒径分布不均匀,且有柱状晶粒出现。随Sb_2O_3掺杂量增大,(Ba_(0.7_Sr_(0.3))Ti_(1.005)O_3基陶瓷居里温度及介电常数峰先增大后减小。提高(Ba_(0.7_Sr_(0.3))Ti_(1.005)O_3基陶瓷的烧结温度并延长保温时间有利于改善Sb_2O_3掺杂量较高时(Ba_(0.7_Sr_(0.3))Ti_(1.005)O_3基陶瓷室温的介电性能。

The microstructures and dielectric properties of Sb2O3-doped（Ba0.7Sr0.3）Ti1.005O3（BST）ceramics for capacitor applications prepared by conventional solid state method were investigated with variation of Sb2O3 content and different sintering process by scanning electron microscope,X-ray diffractometer and LCR measure system.It is found that with the increase of Sb2O3 addition content,（Ba0.7Sr0.3）Ti1.005O3 ceramics transform from single phase solid solution with cubic perovskite structure to multiphase compounds.And Sb^3＋ ions mainly occupy the Asites of perovskite structure in（Ba0.7Sr0.3）Ti1.005O3 ceramics with excessive TiO2.The abnormal grain growth accompanied by the appearance of cylindroid grains and nonuniform distribution of grain size are observed in（Ba0.7Sr0.3）Ti1.005O3 ceramics with high Sb2O3 concentration.The Curie temperature and dielectric constant maximum of（Ba0.7Sr0.3）Ti1.005O3 ceramics increase and then diminish with the increase of Sb2O3 doping content.At room temperature the dielectric properties of（Ba0.7Sr0.3）Ti1.005O3 ceramics with high Sb2O3 content can be improved by properly increasing the sintering temperature and prolonging the sintering process.