Li填充的A3B8CO21型化合物的结构与微波介电性能调控研究

The low temperature sinterable microwave dielectric ceramics are playing a more and more important role in the low cost and minimization of components in commercial communication system. In order to explore high performances microwave dielectric ceramics with medium or high dielectric constant and low sintering temperature. On the base of previous researches on A3B8O21 type ceramics with hexagonal ring structure built by six corner and edge-shared oxygen octahedra, the compositions were firstly designed by Li+ inserting the centre of 6-fold vacancy to enhance the sum of ionic polarizabilities and the compactness of the structure, K+ substituting in A-site and different cations co-substituting to form order-disoder distribution at B site. Then the A3B8CO21 type ceramics are synthesized and prepared, and theirs crystal structure, phonon structure and microstructure, vibrational spectrum, and dielectric properties are investigated. The effects of the variations of composition, structure on properties and its mechanism are summarized and discussed, which will do help to the selection and properties optimization of novel Li-based A3B8CO21 type microwave dielectrics.

可低温烧结的微波介电材料在现代通讯工具的小型化、集成化与低成本化过程中正发挥着越来越大的作用。为了探索固有烧结温度低和高性能的新型中高介电常数微波介电材料，本项目拟在氧八面体共顶与共边连接形成的六元环结构A3B8O21型化合物的研究基础上，首先根据其晶体结构特征，将Li+引入到原来是空的六元环中心位置（C位）以提高单位晶胞体积内的总离子极化率和结构的致密度，然后通过不同离子取代进入A3B8O21结构中氧八面体外的A位，同时在氧八面体内的B位通过复合取代以设计不同类型的有序-无序占位，然后合成与制备A3B8CO21型化合物，系统研究其结构（晶体结构、声子结构与显微结构）、晶格振动特性与介电性能，探讨其不同组成、结构变化对微波介电性能的影响及机制，从而为可低温烧结的Li基六元环结构微波介电材料新体系的选择与性能优化供理论。

低温烧结的微波介电陶瓷在现代通讯工具的小型化、集成化与低成本化过程中正发挥着越来越大的作用。为了探索固有烧结温度低和高性能的新型中高介电常数微波介电材料，本项目在氧八面体共顶与共边连接形成的六元环结构A3B8O21型化合物的研究基础上，首先根据其晶体结构特征，将Li+引入到原来是空的六元环中心位置（C位）以提高单位晶胞体积内的总离子极化率和结构的致密度，然后通过不同离子取代进入A3B8O21结构中氧八面体外的A位，同时在氧八面体内的B位通过复合取代以设计不同类型的有序-无序占位，然后合成与制备Ba3Nb4-4xTi4+5xO21、Ba3Ta4-4xTi4+5xO21、Ba3Ta4-xVxTi4O21、LixBa3M4-xTi4+xO21等A3B8CO21型化合物，系统研究其结构（晶体结构、声子结构与显微结构）、谱学特性（拉曼与远红外反射谱）与介电性能，探讨其不同组成、结构变化对微波介电性能的影响及机制，从而为可低温烧结的Li基六元环结构微波介电材料新体系的选择与性能优化供理论。目前在ACS Sustainable Chem. Eng.、Journal of the European Ceramic Society、Ceramic International、Journal of the American Ceramic Society、Journal of Alloys and Compounds 、Materials Chemistry and Physics、J.Mater Sci:Mater Electron等发表标注基金资助论文46篇，申请发明专利6件，获得2017年度广西自然科学奖二等奖1项（第3完成 人）。