声学换能器用高Tc压电陶瓷的分类制备与高温性能的微结构机理研究

Piezoelectric transducers and sensors are widely used in various scientific and industrial fields, and the key elements in these devices are made of piezoelectric materials. The rapidly expanding demand on piezoelectric transducers and actuators working under harsh environments requires the development of piezoelectric ceramics with significantly improved temperature resistance. Based on the application requirements of transducers, the present project aims to fabricate three types of piezoelectric ceramics, including new bismuth-based perovskite, tungsten-bronze-type codoped lead metaniobate, and bismuth-layered ceramics, with a high Tc and still excellent piezoelectric properties. These are to be achieved by means of introducing MPB via compositing, enhancement of structural stability via multi-lattice site codoping, and modification of fabrication and poling procedures. Furthermore，by analyzing the relationship between the performance of materials and devices，we targets to improve the design and fabrication of relevant transducers. Moreover, by systematically investigating the microstructural and electrical properties of materials of different types or composition, particularly the piezoelectric, ferroelectric and dielectric parameters at elevated temperatures, the project targets to achieve a deep understanding of the relationship between the performance and microstructural characteristics, the physical mechanisms of the modification effects of compositing and codoping, the structural factors governing Tc, and the thermal depolarization phenomena, so as to improve the relevant physical theory of ferroelectrics. The project is of great importance from both theoretical and application points of view.

电换能器和传感器广泛应用于各种科技与工业领域，其核心功能部件是压电材料。随着各种领域对所使用的换能器及传感器耐高温性能要求的不断提高，新型高居里温度(Tc)压电陶瓷的开发日益迫切。本项目拟基于换能器的应用，通过多元复合引入准同型相界（MPB）、多位共掺杂提高稳定性、及制备与极化工艺优化等方法，开发综合性能优异的新型铋基钙钛矿、钨青铜结构偏铌酸铅和铋层状结构三类压电陶瓷材料，以满足不同器件的高温使用要求。在此基础上，结合材料性能与器件性能的关系分析，促进换能器等的改进与制备。另外，通过对不同类及不同组成材料的微观结构与综合电性能，尤其是高温电性能关系的系统研究，了解复合及共掺杂对各类材料高温压电性能的改进机理、相关Tc变化的微结构根源及高温退极化机理，完善相应的铁电物理理论。本项目研究兼具重要理论意义与实用价值。

压电换能器和传感器广泛应用于工业和国民经济的各个领域，其核心功能部件是压电材料，主要是压电陶瓷材料。随着各种领域对所使用的换能器及传感器耐高温性能要求的不断提高，新型高居里温度(Tc)压电陶瓷的开发日益迫切。本项目的内容主要是基于换能器的应用，通过多元复合引入准同型相界（MPB）、多位共掺杂提高稳定性、及制备与极化工艺优化等方法，制备了综合性能优异的新型铋基钙钛矿、钨青铜结构偏铌酸铅和铋层状结构三类压电陶瓷材料，以满足不同器件的高温使用要求；在此基础上，结合材料性能与器件性能的关系分析，促进了换能器等的改进制备，并通过对不同类及不同组成材料的微观结构与综合电性能，尤其是高温电性能关系的系统研究。. 项目的主要成果包括：1）制备了系列高温中高温和超高温三类新型高TC 压电陶瓷材料，包括d33在300pC/N,TC达400oC的钙钛矿结构掺杂压电陶瓷，d33在70pC/N,TC达500oC的LiLa,LiMn掺杂PN系压电陶瓷，及d33在15pC/N以上,TC达700oC以上的共掺及复合体系的铋层状压电陶瓷。2)通过微观结构与性能关系分析，尤其是变温综合研究，提出了几类退极化温度差别概念，3）探讨了复合及共掺杂对各类材料高温压电性能的改进机理、相关Tc变化的微结构根源及高温退极化机理，完善相应的铁电物理理论。该项目属于应用基础研究，对相关高温换能器和传感器的制备改进也有重要实际促进作用。基于该项目资助，目前已发表SCI论文8篇，获授权国家发明专利2项，国际会议邀请报告8次。培养研究生获国家国家奖学金2次，国际会议海报奖1次。项目后续还将进一步推进商业应用，力争实现真正的生产力转化，促进经济发展。