Preparation and dielectric properties of X9R core-shell BaTiO₃ ceramics coated by BiAlO₃-BaTiO₃

详细信息    查看全文

• 作者：Mengying Liu^a ; Hua Hao^a ; ^{haohua@whut.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Weijin Chen^a ; Dongdong Zhou^a ; Millicent Appiah^a ; Binzhi Liu^a ; Minghe Cao^a ; Zhonghua Yao^a ; Hanxing Liu^a ; ^{lhxhp@whut.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Zishan Zhang^b
• 关键词：Dielectric properties ; Core&ndash ; shell structure ; Impedance spectroscopy
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：42
• 期：1
• 页码：379-387
• 全文大小：3676 K

文摘

The typical “core–shell” structure in BT ceramics can easily obtain double dielectric anomalies, which greatly improve the dielectric temperature stability for multilayer ceramic capacitors. In this paper, BaTiO₃ particles were coated with 0.3BiAlO₃–0.7BaTiO₃ shell [xBT@(0.3BA–0.7BT)] by a sol–gel method. Core–shell structure was proved to exist in ceramic grains by transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS). High-temperature X9R dielectrics were obtained when x=0.3 and 0.2, with a high dielectric constant (~1200) and low dielectric loss (<2.0%). Furthermore, the impedance data was fitted by an effective 4RC equivalent circuit, which could be assigned to the core, the shell, the grain boundary, and the ceramic/internal electrode interface regions. The activation energy of the core was found to decrease with x decreasing, while opposite tendency exists in the shell and the grain boundary.