磁电耦合高温压电固溶体的形成和结构性能调控

High temperature piezoelectric solid solutions with magnetoelectrical coupling properties, on the one hand, have urgent applications on oil well detection and health monitoring and engine fuel injection, on the other hand, will be potential candidates for developing next generation multi-state memories and transducers being response to mechanical, electrical and magnetical fields. This proposal will focus on BiFeO3-BaTiO3/PbTiO3 high temperature piezoelectric solid solutions. The long range magnetic order will be introduced in the ferroelectric phase boundaries to form the magnetic phase boundaries. The high temperature insulation, piezoelectric and magnetoelectrical properties will be enhanced by modifying the phase structure, ferroic domains and the grain morphologies and size of solid solutions. The key processes and techniques to modify and characterize the microstructures will be explored. The piezoelectric responses of solid solutions and their hierarchical structure, the origin and physical mechanism of magnetoelectric effects will be investigated. The measurement techniques of piezoelectrical and magnetoelectrical properties of BiFeO3 based solid solutions will be investigated under the applied external fields. The effects of phase structure evolution and the movement of ferroic domains on the piezoelectrical and magnetoelectrical properties under multiple applied fields will also be investigated by using the thermal dynamics analysis and phase field simulations. The expert databases of phase diagram, piezoelectric and elastic parameters of BiFeO3-BaTiO3/ PbTiO3 high temperature piezoelectric solid solutions will be built up. The thermal dynamic models to understand the coupling mechanics will be developed. This project will provide novel academic ideas for optimizing the structure and properties of magnetoelectrical high temperature piezoelectric materials, achieving some innovations in material designs and theoretic mechanisms.

具有磁电耦合效应的高温压电固溶体，一方面，在油井探测、健康监测和发动机燃油喷射等领域有迫切的应用需求；另一方面，是发展新一代力、电、磁多态存储器和换能器潜在的候选材料。本项目以铁酸铋-钛酸钡/钛酸铅高温压电固溶体为重点，在铁电相界附近，引入长程磁有序，形成磁性相界；通过对相结构、铁性畴和晶粒尺寸的调控，提高固溶体的绝缘性、高温压电性能和磁电耦合效应。探索微结构调控和表征的特殊工艺技术；研究固溶体的压电活性和结构本质、磁电耦合效应的来源和物理机制；研究外场作用下，固溶体压电/磁电性能的测量技术；用热力学分析和相场模拟研究外场作用下相结构变化、铁性畴运动对压电/磁电性能的影响。建立铁酸铋-钛酸钡/钛酸铅压电固溶体相图、压电和弹性参数专家数据库、定量理解耦合机制的热力学模型。本项目为磁电耦合高温压电材料的结构性能优化提供了新的学术思想，在材料体系设计和理论机制研究方面有所创新。

具有铁电铁磁效应的高温压电固溶体，一方面在油井探测、油气管道监测和发动机燃油喷射等领域有迫切的应用需求；另一方面，是发展新一代力、电、磁多态存储器和换能器潜在的候选材料。本项目以铁酸铋-钛酸钡/钛酸铅高温压电固溶体为重点，通过组分设计、微结构调控和晶粒尺寸优化，获得了系列化性能优越的BF-PT/BT基多元系压电陶瓷材料，陶瓷的居里点和退极化温度和压电系数达到了预定指标，并且可以在很宽的范围内按需调控，以满足不同工况的需求；采用特殊工艺和测试技术，实现了对固溶体相结构、铁性畴和晶粒形貌尺寸的调控和表征，揭示了材料微结构、极化机制对铁电、压电和铁磁性能的影响。发现了陶瓷中存在少量的第二相，对铁磁性的提高有显著贡献，并且没有引起铁电、压电性能和绝缘性的明显恶化；揭示了外场作用下铁酸铋系高温压电材料的相变规律、压电活性和大应变的结构起源；建立了铁酸铋基高温压电固溶体相结构、相变温度、介电压电参数、弹性常数等结构性能参数专家数据库，设计制备了高温压电传感器和换能器，发现基于铋系压电陶瓷材料的水声换能器呈现出传统PZT压电陶瓷所不具备的优点，可望用于研制高清晰度成像声呐换能器。

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