高度取向PIN-PMN-PT基弛豫铁电细晶织构陶瓷的合成机理与性能优化研究

Lead indium niobate-lead magnesium niobate-lead titanate (PIN-PMN-PT) based ternary relaxor ferroelectric textured ceramics are considered as key functional materials with broad application prospects, due to the potential to possess high phase transition temperature, high coercive field and excellent piezoelectric performance. However, the research progress on texturing this ternary system has been limited because of the compositional diversity of the system and the lack of theoretical basis in texturing etc. In this project, we propose to create a novel strategy to fabricate PIN-PMN-PT based textured ceramics based on sol-gel method and templated grain growth technique (TGG). The effects of matrix precursor gel quality, template composition/size/amount, growth aids and processing parameters on reaction and interdiffusion behaviors, boundary migration, liquid phase composition and layer thickness, and epitaxial growth behavior at template-matrix interfaces will be studied during the nucleation and growth of templated grains. The template-matrix interface control strategy will be explored in detail and the model corresponding to mass transport towards this crystallization interface will be established to direct oriented grain growth. Then the crystallographic texture mechanism for PIN-PMN-PT ternary system will be proposed. After that, the effects of compositional design, phase structure, oriented grain size and domain structure etc. on dielectric, piezoelectric, ferroelectric and pyroelectric properties of the textured ceramics will be investigated. The physical origin of giant piezoelectric properties in PIN-PMN-PT ternary textured ceramics will be explored. Finally, we expect to achieve highly <001> oriented PIN-PMN-PT based textured ceramics with gaint electrical performance. This work will provide experimental support and theoretical basis for designing and fabricating novel textured ceramics with tailored performance in the future. Most importantly, these textured PIN-PMN-PT ceramics will provide new materials for the development of next generation electromechanical devices, especially for devices with a broad working temperature range and a large driving field.

PIN-PMN-PT基弛豫铁电织构陶瓷以可望兼顾高相变温度、大矫顽场和高压电性能等优势，具有广阔的应用前景。然而体系组成的复杂性及相关织构理论的缺失等因素制约了其研究发展。本项目拟采用溶胶凝胶织构新技术制备沿[001]c择优生长的PIN-PMN-PT基细晶织构陶瓷。深入研究凝胶基体和模板籽晶性质、生长助剂、合成参数等对晶粒定向生长时基体-模板界面的反应及迁移速率、液膜层性质及离子扩散情况、外延生长规律的影响，阐明其界面调控机制并建立相应的液膜传质模型，提出该陶瓷体系的织构机理。然后，系统研究组分设计、晶相结构、晶粒尺寸、电畴性质等对织构陶瓷电学性能的影响规律，探讨高压电性能产生的缘由，最终获得沿[001]c高度取向、高性能兼顾高相变温度的三元系织构陶瓷。本研究可为新一代高性能织构材料的设计、制备技术和性能调控奠定实验及理论基础，也为新一代大功率机电器件和高温压电器件提供可靠的高性能新材料。

PIN-PMN-PT基弛豫铁电织构陶瓷以可望兼顾高相变温度、大矫顽场和高压电性能等优势，具有广阔的应用前景。然而体系组成的复杂性及相关织构理论的缺失等因素制约了其研究发展。本项目基于两步钶铁矿前驱体法结合模板籽晶生长技术制备了沿[001]c取向度高达94%的PIN-PMN-PT基细晶织构陶瓷。深入地研究了基体和模板籽晶性质、生长助剂、合成参数等对晶粒定向生长时基体-模板界面的反应及迁移速率、液膜层性质及离子扩散情况、外延生长规律的影响，阐明了其界面调控机制并建立了相应的液膜传质模型，形成了该陶瓷体系的织构机理。然后，系统地研究了组分设计、晶相结构、晶粒尺寸、电畴性质等对织构陶瓷电学性能的影响规律，揭示了高压电性能产生的缘由，实现了织构陶瓷电学性能的大幅度提高，获得了高场压电常数d33高达1620 pC/N、机电耦合系数k33为0.84、矫顽场Ec约为8.3 kV/cm、三方-四方相变温度Tr-t和居里温度Tc分别为122℃和203℃的高性能兼顾高相变温度的三元系PT基弛豫铁电织构陶瓷。本研究为新一代高性能织构材料的设计、制备技术和性能调控奠定了实验及理论基础，也为新一代大功率机电器件和高温压电器件提供了可靠的高性能新材料，具有重要的工程应用价值和理论研究意义。在该基金的资助下, 在本领域国际顶级SCI学术期刊发表高水平原创性研究论文10篇，申报了国家发明专利6项，在学术会议上做报告12次，包括国际会议上的英文邀请/口头报告5次，两次获会议“最佳论文奖”，培养毕业硕士生2名，正在培养博士生3名和硕士生1名。