新型钨锰铁矿结构AZrNb2O8介质陶瓷组分调制、结构与微波介电性能研究

With the rapid development of the core components of microwave communication industry, new dielectric ceramic materials are urgently needed for the tendency. Wolframite-structure AZrNb2O8 dielectric ceramics are investigated with the emphasis on the relation of structure and properties by wet chemical process. Based on the research about extrinsic impact of dielectric properties caused by different microstructure factors, the characteristics, such as bond energy, energy band, density of electronic states and phonon vibration modes, are calculated with the guidance of chemical-bond dielectric and first principle theory. Combing with XRD structure refinement, the origin of microwave dielectric properties from crystal structure and A-site ions with different polarization is analyzed. With the help of far-infrared spectrum analysis the description and confirmation of the phonon vibration mode are firstly performed, and then the intrinsic dielectric response contributed by phonon elementary excitation is explored. Based on the above results, the internal correlation is discussed in detail among crystal structure, chemical bond characteristics and electronic structure with microwave dielectric properties. The aim of project is expected to reveal the structure origin of wolframite-structure microwave dielectric response and especially clarify A-site ions modulation mechanism, which would provide the basic guidance of future adjusting material properties. According to the fundamental results, it is of great significance to further control materials' microwave dielectric properties, also provide a scientific basis for both the enrichment research theory of microwave dielectric materials and the development of new functional materials' response theory.

针对微波通信领域核心元器件产业的迅猛发展对新型介质陶瓷材料的迫切需求，本项目以钨锰铁矿结构AZrNb2O8介质陶瓷为研究对象，利用湿化学工艺以工艺设计和性能/结构解析为研究重点。在研究不同微结构因素对非本征介电性能影响基础上，以晶体化学键的介电与第一性原理理论为指导计算晶体键能、能带、电子态密度及声子振动模等特性，结合XRD结构精修，表征晶体结构及A位离子极化率差异对介电性能的影响根源；借助远红外光谱技术实现声子振动模的描述与指认，探究声子元激发对介电响应本征贡献，建立晶体结构、化学键特性、电子结构与微波性能的内在联系。项目预期将揭示钨锰铁矿结构陶瓷的本征微波介电响应原理及其结构根源，同时阐明A位离子调制作用机制，给出材料性能调控的基本理论指南。根据本项目的基础研究成果，对后续实施材料性能调控与优化具有重要意义，同时为丰富微波介质材料研究理论，发展新型信息功能陶瓷材料响应原理提供科学依据。

随着微波通信事业的迅猛发展，移动通讯、汽车电话、电视卫星、军用雷达以及全球定位系统等领域对高性能微波器件的需求日益增加，要求不断开发具有优异性能的新型低损耗微波介质材料。针对微波通信领域核心元器件产业的迅猛发展对新型低温烧结材料的迫切需求，本项目以钨锰铁矿结构AZrNb2O8陶瓷为研究对象，利用湿化学工艺以工艺设计和性能/结构解析为研究重点，在研究不同微结构因素对其非本征微波介电性能的影响规律基础上，借助XRD结构精修、复杂晶体化学键的介电理论、第一性原理计算及远红外光谱技术深入分析其晶体结构、化学键特性、电子结构及声子结构与微波介电性能的内在联系。. 采用溶胶凝胶工艺在600 ℃条件下合成ZnZrNb2O8纳米粉体，比固相工艺降低了约300 ℃，且1200 ℃烧结其微波介电性能：εr=27.38，Q·f =66,700 GHz，τf=-38.4 ppm/°C。采用传统固相工艺制备了Zn1-xMnxZrNb2O8 (0.02≤x≤0.1)陶瓷，研究发现在1200 ℃下获得烧结致密的Zn1-xMnxZrNb2O8陶瓷。当烧结温度为1200 °C时，Zn0.9Mn0.1ZrNb2O8陶瓷具有最佳的微波介电性能：εr=29.43，Q·f=44,900 GHz，τf=-5.61 ppm/°C；研究发现在1150 ℃下可获得致密的Zn1-xNixZrNb2O8陶瓷，其中Zn0.96Ni0.04ZrNb2O8配比组分可获得优异介电性能：εr=27.10，Q·f =62,700 GHz，τf=-14.72 ppm/°C。基于上述体系之外，还探索相关研究体系，并取得显著进展。 本课题通过对陶瓷基体进行离子掺杂，揭示了不同微结构因素对微波介电性能的影响规律，为后续实现微波介电性能的协调优化与超低损耗化奠定基础，为新一代信息功能陶瓷元器件创新提供材料新体系。