高电致应变钛酸铋钠基材料的制备及低场驱动特性研究

As the excellent substitutes for polluting lead-based materials, Bismuth Sodium Titanate (BNT) based piezoelectric functional materials with high electrostrain properties are highly demanded for national defense and public livelihood in the field of key electronic components such as drivers. The technical obstacle of their commercial application lies in the high requirement for driving electric field, which also reflects the essential issue that the strain principle and modification mechanism of the system are not clear. This project focuses on the electro-induced strain characteristics of BNT based system. The research on the strain modification optimization and intrinsic mechanism analysis were carried out based on the chemical modification, supported by the single crystal synthesis by optical floating zone method, enhanced by the engineering optimization of micro-nano structure, and combined with the key factors such as phase structure, micro-nano morphology and crystallization orientation, etc. With the innovative use of the crucible-free, environmentally-friendly and rapid-growth optical floating zone method, the fabrication of high quality single crystals in BNT-based system has been achieved. The modification systems are developed based on chemical modification through ion substitution and compound solid solution; the optimization mechanisms of complex phase cooperation effect and grain size effect are controlled by structural engineering; the regulation law and intrinsic theoretical model of strain characteristics are explained by mechanism analysis. All of these research outcomes provide useful experience reference and scientific support for the design and synthesis of the materials with low field driving and high electrostrain properties, and promote the application of BNT-based electrostrain materials.

具备高电致应变特性的钛酸铋钠基（BNT）压电功能材料是替代污染性铅基材料的优异潜力体系，在驱动器等关键电子元件领域有着重要的国防民生需求，迄今尚未商业化应用的技术瓶颈在于所需驱动电场过高等问题，而这实质上也折射出该体系应变本源机理和调控改性机制不清晰的核心科学问题。本项目聚焦于BNT基体系的电致应变特性，以化学修饰改性为基、光学浮区法单晶合成为体、微纳结构工程优化为翼，结合物相结构、微纳形态、结晶取向等作用要素，协同开展应变改性优化及本征机理解析等研究工作。运用无需坩埚、无污染、生长速度快的光学浮区法实现对BNT体系高质量单晶的高效可控制备。化学修饰开发离子取代和复合固溶的改性体系，结构工程掌握复相协作及晶粒尺寸等效应的优化机制，机理解析阐明应变特性的调控规律与本征理论模型，为低场驱动高应变性能材料的调控设计合成提供经验参考和科学支撑，并推进BNT基体系电致应变材料的基础研究成果走向应用。

具备高电致应变特性的钛酸铋钠基（BNT）压电功能材料是替代污染性铅基材料的优异潜力体系，在驱动器等关键电子元件领域有着重要的国防民生需求，迄今尚未商业化应用的技术瓶颈在于所需驱动电场过高等问题，而这实质上也折射出该体系应变本源机理和调控改性机制不清晰的核心科学问题。本项目聚焦于BNT基体系的电致应变特性，以化学修饰改性为基、微纳结构工程优化为翼，结合物相结构、微纳形态等作用要素，协同开展应变改性优化及本征机理解析等研究工作。化学修饰开发离子取代和复合固溶的改性体系，结构工程掌握复相协作及晶粒尺寸等效应的优化机制，机理解析阐明应变特性的调控规律与本征理论模型，为低场驱动高应变性能材料的调控设计合成提供经验参考和科学支撑，并推进BNT基体系电致应变材料的基础研究成果走向应用。.总的来说，本研究工作通过对BNT体系MPB组分的多元复合改性研究，掌握了调控BNT体系电致应变性能的调控规律，阐明了BNT体系中的大电致应变特性主要来源于电场激发的遍历性弛豫相与铁电相之间可逆相变，表明无论是通过组分设计或是温度调节均可以使样品达到铁电相和弛豫相共存的状态，从而有效调控BNT体系的电致应变性能。并开发了系列具有优良电致应变性能的无铅压电陶瓷组分，在大幅提高电致应变效率的同时有效降低了驱动电场，理论与实践结合为促进BNT电致应变性能的实际应用提供有益参考。