毫米波复合旋磁铁氧体材料的低温烧结机制及离子占位机理研究

In this project, in order to meet the development of miniaturization, integration and high frequency of phased array radar systems and phase shifters, the low temperature co-fired system of high performance and low loss gyromagnetic ferrites were investigated. The project intended to start with the crystal structure theory and the liquid phase sintering mechanism of gyromagnetic ferrites, and the composite gyromagnetic ferrites with high saturation magnetization, high rectangle ratio, high curie temperature, low ferromagnetic resonance line width and low dielectric loss were prepared through the methods of low-melting-point composite oxides doping, nanocrystalline implantation and recombination of multiple gyromagnetic ferrites. Meanwhile, the problems of low temperature sintering, low loss and high performance of gyromagnetic ferrites were systematically solved via the establishment of the dynamic model of low-temperature sintering, the study of reaction method and mechanism of nanocrystalline chemical synthesis, the analysis of the mixed sintering technology of nanocrystalline and micron crystal, the discussion of recombination of multiple gyromagnetic ferrites technology and the mechanism of ion occupation, which lay the foundation for the millimeter-wave LTCC phase shifter manufacturing.

本项目以实现相控阵雷达系统及移相器的小型化、集成化、高频化发展为研究目标，以低损耗、高性能旋磁铁氧体材料的低温烧结体系为主要研究对象，拟从旋磁铁氧体的晶体结构理论及液相烧结机制入手，通过低熔点复合氧化物掺杂、纳米晶植入和多元旋磁铁氧体复合等方法制备出具有高饱和磁化强度、高矩形比、高居里温度、低铁磁共振线宽、低介电损耗的复合旋磁铁氧体材料。通过低温烧结动态模型的建立，纳米晶化学合成反应方法及机理的研究，纳米晶和微米晶混合烧结技术的分析，多元旋磁铁氧体复合技术及离子占位机理的讨论，系统的解决旋磁铁氧体的低温烧结、低损耗及高性能等问题，为毫米波LTCC移相器的制造工艺技术奠定基础。

本项目以毫米波LTCC器件的小型片式化、集成化为研究目标，基于LTCC技术，按照理论分析、模型建立、材料设计三位一体的研究模式，实现了从材料分析到研制途径的综合调控。重点探索了离子取代机制、多元低熔点复合氧化物掺杂机理、纳米晶种植入等LTCC技术应用的关键瓶颈问题。完成了液相烧结传质机理与动力学原理分析；建立了液相烧结模型和离子扩散模型；采用Rietveld精修讨论了离子占位和分布情况；探究了离子占位分布与A-B位超交换作用对饱和磁化强度的影响；采用溶胶-凝胶法成功制备了锂锌纳米晶，研究了纳米晶与多元低熔点氧化物的联合掺杂机制；分析了纳米晶的辅助烧结机理；讨论了纳米晶对铁氧体材料激活能的调控方式。最终，获得了兼具低温烧结和优异高频磁介特性的毫米波旋磁材料。