Ba基复合钙钛矿陶瓷的有序/无序相变、畴结构与微波介电性能

In the present project, the order/disorder transition, domain structures and microwave dielectric chracteristics of Ba-based complex perovskite niobates ceramics are systimatically investigated, and the variation rules of domain structure and microwave dielectric characteristics with composition and processing conditions are revealed. The domain structure is tailored and controlled by adjusting the sintering temperature and order/disorder transition temperature, and subsequently achieve the ultra-low dielectric loss. The principles for materials design and structure/property control for microwave dielectric ceramics with complex perovskite structure are revealed, and the key foundmental scientific issues are going to be addressed for developing new medium-K microwave dielectric ceramics with utra-low dielectric loss. Some Ba(M'1/3Nb2/3)O3-based microwave dielectric ceramics with superior characteristics are expected to be developed.

本项目拟系统研究Ba基复合钙钛矿铌酸盐陶瓷的有序/无序相变、畴结构与微波介电性能，揭示其畴结构与微波介电性能随成分与制备条件的变化规律。通过控制烧结温度与有序/无序相变温度实现畴结构的调控、进而追求其超低损耗化。揭示复合钙钛矿微波介质陶瓷的材料设计以及结构性能调控原理，为超低损耗中介电常数微波介质陶瓷新材料的发展解决若干基础科学问题。研究出几种性能优越的Ba(M'1/3Nb2/3)O3-基微波介质陶瓷。

Ba基复合钙钛矿陶瓷是最为重要的低损耗微波介质材料，在移动通讯基站与卫星通讯等领域有着十分重要的应用。该类材料最大的技术挑战是如何实现超低损耗化，而其超低损耗化的根本途径是有序畴结构调控。该项目系统研究了Ba基复合钙钛矿铌酸盐陶瓷的有序/无序相变、畴结构与微波介电性能，揭示了其畴结构与微波介电性能随成分与制备条件的变化规律。发现该类材料微波介电性能、尤其是品质因数不仅取决于有序度，更取决于有序畴尺寸/分布、以及畴壁结构。得出的结论是，高有序化程度、均匀细小的有序畴、以及低能态畴壁结构是复合钙钛矿微波介质陶瓷超低损耗化的根本保证。通过控制烧结温度与有序/无序相变温度实现了畴结构的调控、进而实现了其超低损耗化。揭示了复合钙钛矿微波介质陶瓷的材料设计以及结构性能调控原理，为超低损耗中介电常数微波介质陶瓷新材料的发展解决了若干基础科学问题。在此基础上，研究出了几种性能优越的Ba(M'1/3Nb2/3)O3-基微波介质陶瓷，最佳Qf值Qf超过110,000GHz。有关研究成果获得实际应用。