基于相结构和缺陷的KNN基无铅压电陶瓷温度稳定性的影响机理研究

In order to meet the demand of practical application, improving temperature stability of high-performance KNN-based lead-free piezoelectric ceramics has become one of the hotspots for the research in the field of functional material, in recent years. Previous researches indicated that macroscopic electric properties related to dynamic ferroelectric domain behavior possess a strong temperature dependence. Phase structure and defect play important roles in ferroelectric temperature stability. As well as, piezoelectric and electromechanical properties are affected by phase structure and defect, respectively. At present, the researches that the quantitative analysis of ferroelectric temperature stability for KNN-based lead-free piezoelectric ceramics have been insufficient. And the effects of phase structure and defect on temperature stability of electric properties are not clear. Therefore, in this study, the stability of electric properties for KNN-based lead-free piezoelectric ceramics under temperature field will be investigated, including the effect of phase structure (especially polymorphic phase transition (PPT)) on ferroelectric temperature stability and piezoelectric temperature stability, and the effect of defect (symmetry of defect dipole, order and motion of oxygen vacancy) on ferroelectric temperature stability and electromechanical temperature stability. Based on dynamic ferroelectric domain behavior, the scientific questions are crucial considered: the effects of phase structure and defect on temperature stability for KNN-based lead-free piezoelectric ceramics and their physical mechanism; the inner relation between ferroelectric and piezoelectric temperature stability or electromechanical temperature stability. It is expected to achieve the high-performance lead-free piezoelectric ceramics with improved temperature stability.

增强高性能KNN基无铅压电陶瓷的温度稳定性，以满足实际应用的需求，如今已成为功能材料领域的一个研究重点。研究表明，与铁电畴动态行为相关的各宏观电性能具有强的温度依赖性；而相结构和缺陷在铁电温度稳定性中扮演重要角色，它们也分别影响压电、机电性。目前，KNN基压电陶瓷铁电温度稳定性的定量研究并不充分；且相结构和缺陷在其电性能温度稳定性中所起的作用也尚不明确。故本项目开展温度作用下KNN基无铅压电陶瓷电性能的稳定性研究，主要包括相结构（特别是多晶型相转变PPT）对其铁电、压电温度稳定性的影响，和缺陷（缺陷偶极子的对称性，氧空位的排序及运动）对其铁电、机电温度稳定性的影响。立足于KNN基无铅压电陶瓷的铁电畴动态行为，拟重点解决的关键科学问题为：相结构和缺陷对其温度稳定性的影响和物理机理，以及其铁电与压电、机电温度稳定性的关联和增强机制。项目预期获得兼具高性能和优异温度稳定性的无铅压电陶瓷。

高性能无铅压电陶瓷因其环境友好特性，近年来成为材料科学与工程领域的研究热点之一；其中性能优异的KNN基无铅压电陶瓷备受关注。与铁电畴动态行为相关的各种宏观电性能具有强的温度依赖性；而相结构和缺陷在铁电温度稳定性中扮演重要角色，它们也分别影响压电、机电性。本项目开展了温度作用下KNN基无铅压电陶瓷电性能的稳定性研究，包括（1）相结构（单一相、多晶型相转变PPT）对其铁电、压电温度稳定性的影响，（2）缺陷（缺陷偶极子的对称性，氧空位的排序及运动）对其铁电、机电温度稳定性的影响。立足于KNN基无铅压电陶瓷的铁电畴动态行为，重点解决了相结构和缺陷对其温度稳定性的影响和物理机理，以及其铁电与压电、机电温度稳定性的关联和增强机制。项目获得兼具高性能和优异温度稳定性的KNN基无铅压电陶瓷，部分性能可以满足实际应用的需求。在ACS Applied Materials & Interfaces，Journal of Materials Chemistry C，Journal of the American Ceramic Society, Ceramics International等期刊共发表SCI论文11篇; 申请发明专利2项，其中一项已授权。