铁酸铋-钛酸钡无铅压电陶瓷织构化工艺技术及服役特性研究

BiFeO3-BaTiO3 lead free piezoelectric material are important environment-friendly piezoelectric solid solutions due to the high Curie temperature as well as good temperature stability of dielectric and piezoelectric properties. This project is to carry out the research from the whole chain of "material design and preparation-mechanism analysis-device application" to improve the piezoelectric properties and study the electric properties under service conditions (complex and multiple fields, such as electric field, stress field and temperature). Combination of the characteristics of "domain engineering" and "crystallographic texturing", strong magnetic field assisted Reaction Template Grain Growth (RTGG) technology will be used to prepare textured ceramics with highly preferred orientation and dense morphology to improve their piezoelectric properties. The mechanism of material performance under service conditions will be studied. And the new-type lead-free piezoelectric actuator without inner electrode and glue based on BiFeO3-BaTiO3 ceramics will be designed. The fabrication process of BiFeO3-BaTiO3 textured ceramics by RTGG technology will be explored carefully. The growth mechanism of template grains under the assistance of strong magnetic field will be analyzed. The relationship between aging as well as fatigue properties and compositions along with microstructure of materials will be discussed. The relationship between reliability of piezoelectric materials and actuators under stress, temperature and electric field and the properties of the piezoelectric materials will be studied. This project will provide a new technology for the preparation of BiFeO3-BaTiO3 piezoelectric materials, and break down the barrier between microstructural design and device application of lead-free piezoelectric materials, which can further promote the scientific research and application of lead-free piezoelectric materials and devices.

铁酸铋-钛酸钡固溶体不含铅、居里点高、且具有良好介电和压电温度稳定性，是一种重要环境友好型无铅压电材料。本项目针对其压电活性低和多物理场（温度、应力和电场）协同作用下服役特性研究匮乏两大关键问题，拟从“材料设计制备-机理分析-器件应用”全链条展开研究。结合“工程畴”和“晶粒定向”特点，采用强磁场辅助反应模板晶粒生长新方法制备织构陶瓷，提升压电性能；探究材料服役性能调控机理；在此基础上设计开发新型无需内电极和粘接的压电驱动器。探索制备铁酸铋-钛酸钡固溶体织构化工艺；分析强磁场辅助作用下多铁性材料的模板晶粒外延生长机理；研究织构陶瓷老化和场致疲劳等服役特性与微结构之间关系；讨论多物理场作用下压电驱动器的可靠性与材料服役性能关系。本项目为调控铁酸铋-钛酸钡性能提供了新技术和新思路，能够打破无铅压电材料微结构设计与器件应用之间壁垒，推进无铅压电材料研究和器件化应用。

与其他钙钛矿型无铅压电固溶体相比，铁酸铋-钛酸钡固溶体具有居里温度高，烧结温度低，介电和压电温度稳定性较好等优点，是一种重要的高温无铅压电材料，在航空航天、石油勘探和化工检测领域有潜在的应用。提升该固溶体的压电性能，澄清服役特性（场致应变和压电温度稳定性的调控机制不清）能够进一步推动该固溶体的产业化应用。围绕以上关键内容，申请人及团队探索了反应模板法制备织构陶瓷的关键工艺，使用原位同步辐射、透射电镜、铁电压电测试系统等多种表征手段并对其构效关系及调控方法进行了研究，获得了压电性能优异的织构陶瓷，分析了压电性能提高的微观机理，厘清了场致应变结构起源，澄清了介电、压电性能的温度依赖性及调控方法，并在此基础上开发了压电驱动和传感等原型器件。具体研究成果如下：1）以钛酸钡为模板，采用流延工艺制备了<001>取向铁酸铋-钛酸钡陶瓷，获得了织构化的关键制备工艺和织构化机理。2）分析了相界附近不同物相结构场致应变结构起源，并提出了应变调控机制。3）研究了介电、压电温度稳定性与物相结构、化学均匀性、晶粒尺寸和极化工艺之间的内在联系，并提出了提高温度稳定性的方法。4）采用流延工艺制备了多层压电驱动器，研究了温度和电场作用下压电系数的应变输出特性的稳定性；设计了压缩式压电传感器，分析了灵敏度的温度稳定性。本项目从组分设计、微结构调控、性能表征与机制分析和原型器件装备等紧密结合的全链条出发开展了铁酸铋-钛酸钡压电陶瓷性能调控和器件应用的基础研究，在Acta Materialia，Applied Physics Letters和 Journal of the European ceramics society 等期刊上共发表SCI论文21篇。本项目的成果为提高压电性能提供新的制备工艺，澄清了压电性能的结构起源，明确了压电温度稳定性的调控机制，探索了其器件化应用，有力的推动了高温压电陶瓷和器件的发展。