标题：Effect of composition on the structure and piezoelectricity of Na0.5Bi4.5Ti4O15-based flexoelectric-type polar ceramics
作者：Kuai, W.J. ;Zhao, M.L. ;Wang, C.L. ;Wang, L.H. ;Wang, J. ;Gai, Z.G. ;Zhang, J.L. ;Yin, N.
作者机构：[Kuai, W.J. ;Zhao, M.L. ;Wang, C.L. ;Wang, L.H. ;Wang, J. ;Gai, Z.G. ;Zhang, J.L. ;Yin, N. ] School of Physics, State Key Laboratory of Crystal Materi 更多
来源：Journal of Alloys and Compounds
摘要：Flexoelectric-type polar ceramics might specify a class of heterogeneous ceramics that possess permanent, macroscopic, flexoelectric-type polarization and thus can exhibit both direct and converse piezoelectric effects without undergoing an electrical poling process. Here we show, by studying series of Na0.5Bi4.5Ti4O15-based nominal compositions, that flexoelectric-type polar ceramics can be synthesized by adding an appropriate amount of excess Bi2O3to Na0.5Bi4.5Ti4O15, whereas the addition of only excess Na2CO3or excess TiO2to Na0.5Bi4.5Ti4O15does not have this effect. The obtained Na0.5Bi4.5Ti4O15+ xBi2O3flexoelectric-type polar ceramics all contain Na0.5Bi4.5Ti4O15and Bi12TiO20phases, and their macroscopic polarization might originate from the partial alignment of distorted TiO6octahedra and BiO5polyhedra that are located within the grain boundary amorphous phases. Because the sodium-modified Na0.5Bi4.5Ti4O15+ 2.25Bi2O3flexoelectric-type polar ceramics were found to have a piezoelectric coefficient, d33, larger than 8 pC/N and a depoling temperature higher than 700 °C, they are thought to have potential piezoelectric applications in the high-temperature region. © 2013 Elsevier B.V. All rights reserved.