复合钙钛矿微波陶瓷的温度系数与结构关系研究及其调控

The increasing demand on microwave components requires microwave dielectric ceramics to possess high permittivity εr, high quality factor Q×f, and near-zero temperature coefficient of the resonator frequency τf. Ba(BI1/3BII2/3)O3 based complex perovskite structure ceramics have been concerned widely due to their extremely high Q×f value. A large amount of research has been done to investigate the mechanism of their dielectric loss. However, how to tune the temperature coefficient in an accurate method and evaluate the quantitative relationship between τf and structural factor in Ba(BI1/3BII2/3)O3 based materials remains to be solved. The project intends to build up the theoretical model of [BO6] oxygen octahedral in complex perovskite structure combining the experimental calculation and theoretical calculation. The mathematic relationship between the structural deformation parameter and temperature coefficient of resonant frequency will be studied so as to illuminate the physical mechanism of temperature coefficient variation. Furthermore, the composition and structure design principle to fabricate microwave dielectric materials, of which the temperature stability of resonant frequency could be controlled simply be structure, will be investigated. The achievement of this project will provide scientific foundation for composition and structure design work.

信息技术的飞速发展要求微波介质陶瓷具备更高的介电常数εr、品质因数Q×f以及近零谐振频率温度系数τf。复合钙钛矿Ba(BI1/3BII2/3)O3基微波陶瓷因其超高Q×f引起了人们广泛的关注，目前针对其Q×f的调控与介电损耗机理研究已日渐成熟，而有关该类材料频率温度系数τf的精确调控及其与结构影响因子的定量关系研究工作仍较为缺乏。本项目拟结合实验分析表征与理论计算模拟构建复合钙钛矿结构微波材料中[BO6]八面体形变与谐振频率温度系数理论关系的模型，建立结构形变量与谐振频率温度系数的数学关系，从结构特征的角度揭示Ba(BI1/3BII2/3)O3基陶瓷频率温度系数变化的物理机制，进而总结频率温度稳定性可控的复合钙钛矿微波材料的结构设计原则，为今后的成分与结构优化设计工作提供科学依据。

复合钙钛矿微波介质陶瓷近年来受到人们的广泛关注。由于其B位两种离子的电荷和半径差别较大，因而倾向于形成有序化排列，这种特殊的结构决定了其高品质因数。本项目选取Ba(Zn1/3Nb2/3)O3作为研究对象，从制备方法改进的角度得到了具有复合钙钛矿结构的Ba(Zn1/3Nb2/3)O3微波介质陶瓷纳米粉体以及高有序度高致密度细晶粒Ba(Zn1/3Nb2/3)O3陶瓷，系统研究了工艺参数对该材料离子有序性、显微组织、微观结构及微波介电性能的影响机制。从离子掺杂的角度制备了A位被Sm离子取代，以及B位被Mg、Ti、Zr等离子取代的Ba(Zn1/3Nb2/3)O3基陶瓷，阐明了各离子掺杂对材料的显微结构、物相组成以及介电性能的影响规律，并探讨了微波介电性能变化的成因，为开发具有应用价值的高性能温度稳定型微波介质陶瓷以及具有大温度系数、可用于温度传感器的材料提供了参考和新思路。