钛酸钡固溶体“芯-壳”纳米复合结构的制备及其高温介电性能的研究

项目名称： 钛酸钡固溶体“芯-壳”纳米复合结构的制备及其高温介电性能的研究

项目编号： No.51272123

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 王晓慧

作者单位： 清华大学

项目金额： 80万元

中文摘要： 高温陶瓷电容器在汽车、石油钻探、航空航天、军工等领域都有着广泛的应用。但目前我国在150-200度高温下使用的X8R/X9R型多层陶瓷电容器(-55-150/200度, 电容变化率（△C/C25）≤±15%)完全依赖进口。因此本课题拟系统地研究BaTiO3-BiScO3、BaTiO3-Na0.5Bi0.5TiO3固溶体系的组成、晶体结构与介电性能关系，探索获得具有高居里温度的铁电固溶体；进一步通过掺杂剂的均匀化学包覆构建core-shell纳米复合结构以满足高温度稳定特性X9R的要求，研究纳米包覆组成、厚度、烧结气氛、烧结工艺（两段式、普通烧结）等对陶瓷微结构与介电温度特性的影响规律与形成机理，建立高温介电陶瓷温度稳定性与纳米尺度微结构控制的技术，研制出具有优异特性的高温陶瓷电容器材料。为制备环境友好的新一代高可靠性高温多层电容器提供科学依据和技术支撑。

中文关键词： 钛酸钡；芯-壳结构；铁电固溶体；介电性；化学包覆

英文摘要： With the increasing demands of passive components which are capable of working at high temperature, much attention has been paid to dielectrics satisfying EIA X8R/X9R specification(-55-150℃/200 ℃,（△C/C25）≤±15% or less), especially for multilayer ceramic capacitors( MLCCs) whose upper limit temperature reach 200℃.High temperature stable MLCCs find wide applications for automobile, oil drilling, aerospace application and military. In this project, The solid solutions BaTiO3-BiScO3、BiYbO3-BaTiO3、BaTiO3-Na0.5Bi0.5TiO3 are synthesized by solid state reactions and chemical method in order to find out good solid solution materials with high Curie temperature(Tc) and good dielectric property. The composition and grain size effect on microstructure and dielectric property will be studied in details. In order to improve the temperature coefficient of capacitance (TCC) for X9R specification, BaTiO3 based solid solution materials with high Tc will be modified with additives to form grain core-shell structure through uniform chemical coating technology. The influnces of the coating layer compositions, coating layer thickness, sintering temperature as well as sintering atmosphere on the ceramic microstructures and high temperature dielectric properties are investigated systematically. Two-step sintering technique is also us

英文关键词： barium titanate；core-shell structure；ferroelectric solid solution；dielectric property；chemical coating