B位复合尖晶石陶瓷的有序/无序相变、畴结构、缺陷与微波介电性能的研究

项目名称： B位复合尖晶石陶瓷的有序/无序相变、畴结构、缺陷与微波介电性能的研究

项目编号： No.11464009

项目类型： 地区科学基金项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 周焕福

作者单位： 桂林理工大学

项目金额： 60万元

中文摘要： 申请者在前期研究工作中发现，B位复合尖晶石陶瓷具有原料便宜、密度小、烧结温度低以及介电性能优异等优点，是一类极具应用潜力的微波介电陶瓷新体系，但目前对该类材料介电损耗的形成机制及其调控机理的研究还很有限。本项目以其为研究对象，借鉴钙钛矿、钨青铜等材料体系的理论研究成果，通过第一性原理和远红外反射光谱研究材料的本征介电常数及介电损耗，揭示该类材料介电损耗的起源。利用原位XRD、Raman光谱、TEM等方法系统研究陶瓷内应力、有序/无序相变、有序度及有序畴、点缺陷等，并探讨以上因素与材料介电损耗的内在关联性，揭示该类材料的组成、微结构和制备工艺对性能的内在影响机制，进而优化材料的微波介电性能，以期获得超低损耗的新型尖晶石微波介电陶瓷。本项目的顺利实施，可以深入认识微波介电材料设计、制备、结构与性能之间的关系等科学问题，丰富微波电介质理论。

中文关键词： 尖晶石；微波陶瓷；有序/无序相变；第一性原理计算；畴结构

英文摘要： In our preliminary study, B site complex spinel ceramics exhibit low cost of raw materials, low bulk densities, low sintering temperatures and excellent dielectric properties, which is a type of novel microwave dielectric ceramic with having a potential application. However, the researches on the formating and controlling mechanisms of dielectric loss of ceramics are very limit. In this project, B site complex spinel ceramics will be studied by using the achievement of theoretic research of perovskite and tungsten bronze materials. Firstly, the intrinsic dielectric constant and loss of ceramics will be studied by first principle and far-infrared reflectance spectroscopy, and the origin of dielectric loss of materials will be revealed. Secondly, the intrinsic stress, ordered/disordered phase transition, ordering degree, ordering domain and point defects of ceramics will be studied using in-situ XRD, Raman and TEM. The relationship between the dielectric loss and the above factors will be discussed. The intrinsic mechanism of the composition, microstructure and preparation technology on the performance will be revealed. Finally, the novel spinel microwave dielectric ceramics with ultralow dielectric loss will be obtained. The accomplishment of this project will provide a deep understanding on a series of scientific problems about the relationship between the design, preparation, structure and properties of the microwave dielectric materials, which enriches the microwave dielectric theory.

英文关键词： Spinel;Microwave ceramic;Odered/disordered phase transition;First principle calculation;Domain structure