材料期刊网

综述了铋层状压电陶瓷的结构特点及性能研究. 铋层状压电陶瓷的结构由(Bi2O2)2+层和钙钛矿层(Am-1BmO3m+1)2-按一定规则共生排列而成. 此处A为适合于12配位的离子; B 为适合于八面体配位的离子，m为一整数，其值一般为1～5. 与钛酸钡(BaTiO3)或锆钛酸铅(PZT)陶瓷相比，铋层状压电陶瓷具有以下特点：低介电常数、高T c、机电耦合系数各向异性明显、低老化率、高电阻率等. 先前研究证明，居里温度不仅与极化原子位移、自发极化强度、A位Bi含量有关，而且还与取代离子的特性诸如离子半径、电负性、核外电子排布有关. 压电活性低是铋层状陶瓷的本质缺点，通常发展该材料的途径为化学取代或晶粒取向技术. 研究材料结构与性能之间的关系有助于发展铋层状压电陶瓷材料.

This paper reviewed the structures and properties of bismuth layer-structured piezoelectric ceramics. The structures of bismuth layer-structured piezoelectric ceramics are built up by the regular intergrowth of (Bi2O2)2+layers and perovskite (Am-1BmO3m+1)2- slabs where A is a combination of cations adequate for 12-coordinated interstices, B is a combination of cations well suited to octahedral coordinated, and m is an integer usually lying to the range 1-5. By comparison with barium titanate (BaTiO3) or lead zirconate titanate (PZT) ceramics, the bismuth layer-structured piezoelectric ceramics are characterized by: (1) lower dielectric constant; (2) higher Curie temperature; (3) stronger anisotropy in electromechanical coupling factors; (4) lower ageing rate; (5) higher resistivity; …etc.. 　　Previous studies showed that Curie temperature depends on atomic displacement of polarization cations, spontaneous polarization, bismuth content in the cubooctahedral cavities, and the nature of the substituting cations such as inonic radius, electronegativities and electronic configuration. An essentially weak point of bismuth layer-structured piezoelectric ceramics is low piezoelectric activity which can be solved by chemical substitution or fabrication methods for orientating the grains in ceramics. It is necessary to study the relationships between structures and properties of bismuth layer-structured piezoelectric ceramics in order to develop the materials.