A位复合钙钛矿结构铁电体的奇异弛豫特性、A位活性及其机理研究

To meet the urgent demand of lead-free piezoelectric materials and devices, a new idea about adjusting the strange relaxor characteristic to obtain excellent electrical properties similar to those of Pb-based relaxors is put forward based on strange relaxor characteristics and A site activity of BNT-based lead-free piezoelectric ceramics with A site complex perovskite. The strange relaxor characteristic, excellent electrical properties and their correlation which are induced by multi-scale of microstructure, defects, domain, grain size under different temperature, electrical field and frequency will be investigated. Mechanism of strange relaxor characteristic, excellent electrical properties will be explained. The effect of A-site ions substitution type and substitution way, A-site ions doping type and doping way, preparation process, sintering atmosphere, outfield on microstructure, mesoscopic structure, relaxor characteristic, electrical properties will be explored. The effective way and theory of adjusting relaxor characteristic, electrical properties will be obtained. The design theory and principles of new materials microscopic-mesoscopic-macroscopic structure for structure construction, excellent performance, relaxor characteristics adjusting of A-site complex perovskite materials will be established. The results of this project will offer some theoretical and practical references for exploring new high performance lead-free piezoelectric ceramics.

本项目针对压电、铁电器件无铅化的迫切要求，基于A位复合钙钛矿型钛酸铋钠(BNT)基无铅材料的奇异弛豫特性与A位活性的特点，提出通过调控其奇异弛豫特性来获得类似铅基弛豫铁电体优异电性能的新思路。通过研究A位复合BNT基陶瓷在不同温度场、电场与频率下微观结构、缺陷、电畴、晶粒尺寸等多尺度效应诱发的奇异弛豫特性、优异电性能以及本质关联，阐明A位复合铁电体奇异弛豫特性与A位活性的作用机理。探讨A位离子取代类型与取代方式、A位离子掺杂类型与方式、制备工艺与气氛以及外场作用对微介观结构、弛豫特性和电性能的调控效应，获得调控弛豫特性和电性能的理论和有效途径，以及通过改变弛豫特性实现A复合弛豫铁电体优异电性的可能并探索其作用机理；建立A位复合钙钛矿类材料的组织构建、优异性能、弛豫特性调控的新材料微观-介观-宏观组织结构设计理论与准则，为探索高性能无铅压电铁电材料提供实验借鉴和理论参考。

本项目针对压电、铁电器件无铅化的迫切要求，基于A位复合钙钛矿型钛酸铋钠(BNT)基无铅材料的奇异弛豫特性与A位活性的特点，提出通过调控其奇异弛豫特性来获得类似铅基弛豫铁电体优异电性能的新思路。通过研究A位复合BNT基陶瓷在不同温度场、电场与频率下微观结构、缺陷、电畴、晶粒尺寸等多尺度效应诱发的奇异弛豫特性、优异电性能以及本质关联，阐明了A位复合铁电体奇异弛豫特性与A位活性的作用机理。探讨了A位离子取代类型与取代方式、A位离子掺杂类型与方式、制备工艺与气氛以及外场作用对微介观结构、弛豫特性和电性能的调控效应，获得了调控弛豫特性和电性能的理论和有效途径，以及通过改变弛豫特性实现A复合弛豫铁电体优异电性的可能并探索了其作用机理；建立A位复合钙钛矿类材料的组织构建、优异性能、弛豫特性调控的新材料微观-介观-宏观组织结构设计理论与准则，提出了BNT基压电活性与弛豫特性的关系，获得了A位压电活性的微观结构来源，即压电活性来源于极化建立的关联有序纳米畴。研究结构可为探索高性能无铅压电铁电材料提供实验借鉴和理论参考。