钛酸钡基介电材料的结构演变、极性微区/畴结构及介电温度稳定性的研究

Wide temperature application of electronic components requires the corresponding dielectrics must have good dielectric temperature stability. In order to solve the problem with great changes of permittivity and poor temperature stability in the vicinity of phase transition for the barium titanate based ferroelectric materials, in this project, BaTiO3 ferroelectric material was chose as the object. Firstly, the performance of materials was improved by using Bi3+ to substitute A site cation and mixations to substitute B site cation. The effects of different preparation technology, process parameters and sintering atmosphere on the phase evolution, characteristics of grain and grain boundary, polar nanoregions/domain structure, chemical valence state and oxygen vacancies of materials were systematically studied. Furthermore, the relationship between the above factors and dielectric properties was discussed, the physical essence of dielectric thermal stability of ceramics was revealed. The control of dielectric thermal stability of ceramics was achieved. Finally, the novel barium titanate based dielectric materials with good temperature stability, high performance and low cost applied in high temperature capacitors were obtained. The implementation of this project will play an important role not only in the study of science problems but also the application technology of dielectric materials.

电子元器件宽温度应用要求相应的介电材料必须具有高的介电温度稳定性。针对目前钛酸钡基铁电材料在相变点附近介电常数变化大、温度稳定性差这一问题，本项目拟以其为研究对象，通过A位选取Bi离子、B位选取不同组合的复合离子对该材料进行取代改性。系统研究不同制备方法、工艺制度和烧结气氛对材料相结构演变、晶粒与晶界特性、极性微区/畴结构、元素的化学状态以及氧空位等进行系统的研究。探讨上述因素与介电特性的内在关联性，揭示其介电温度稳定性的物理本质，实现该类材料介电温度稳定性的调控，以期获得面向高温电容器应用的高性能、低成本的新型钛酸钡基温度稳定型介电材料。本项目的顺利实施，对于介电材料科学问题的研究和应用技术的探索这两个层面来说都具有重要意义。

针对目前钛酸钡基铁电材料在相变点附近介电常数变化大、温度稳定性差这一问题，本项目以其为研究对象，通过A位选取Bi离子、B位选取不同组合的复合离子对该材料进行取代改性。系统研究了不同制备方法、工艺制度和烧结气氛对材料相结构演变、晶粒与晶界特性、极性微区/畴结构、元素的化学状态以及氧空位等的影响。探讨上述因素与介电特性的内在关联性，揭示其介电温度稳定性的物理本质，实现该类材料介电温度稳定性的调控，获得了一系列面向高温电容器应用的高性能、低成本的新型钛酸钡基温度稳定型介电材料。除此之外，设计合成了系列K0.5Na0.5NbO3基温度稳定型高介材料，并对材料的“组成—结构—性能”的关系进行了系统的研究。通过加入一定量的Bi基复合钙钛矿与NaNbO3形成固溶体，优化了NaNbO3的储能特性，获得了系列储能密度大、效率高的新型介电储能材料。从材料科学的角度出发，设计制备了一种性能优异的LiCuNb3O9巨介电常数材料。本项目的研究成果对于介电材料科学问题的研究和应用技术的探索这两个层面来说均具有重要意义。