织构化铌酸钾钠基无铅压电陶瓷的缺陷设计与调控

The piezoelectric ceramics is an important functional materials and widely used in various electrical products. At present, owing to the toxicity of lead element the large scale used Pb(Zr,Ti)O3 seems no longer satify the increasing envriomental requirments. This project was intended to realize the design and regulation of the defect in the textured lead-free ceramics via tape casting process and obtain highly textured Li modified (K,Na)NbO3 ceramics possessing comparable performance with PZT based ceramics. It is about to investigate the effect of the type and concentraton of acceptor doping ions, and tape casting process on the distribution state of defect dipoles in the current materials; how to make use of the feature of defect dipoles and its coupling effect with spontaneous polarization dipoles to achieve the active control of the properties of the textured KNN based ceramics. This work is helpful to acknowledge the origin and the mechanism for the couping effet of two kinds of dipoles. Meantime, it will be of great theoretical and practical significance to promote the development of lead-free piezoelectric ceramics.

压电陶瓷是一种重要功能材料，广泛应用在各种电子信息产品中。目前大量使用的含有有害元素铅的锆钛酸铅(PZT)体系压电陶瓷已经不适应日益提高的环保要求。本项目拟通过织构化工艺实现无铅压电陶瓷中缺陷的设计和调控，以期制备出性能可与PZT基陶瓷相媲美的高择优取向度锂掺杂铌酸钾钠(KNNLN)无铅压电陶瓷。研究受主掺杂离子类型和浓度、流延工艺等对缺陷偶极子分布形态的影响；研究如何利用缔合缺陷偶极子的自身特点以及其与织构化KNNLN陶瓷中本征自发极化偶极子在外场下的耦合效应，实现对织构化陶瓷体系宏观性能的主观调控。此方面工作的开展，利于对压电体系中本征极化子和非本征极化子的起源和两者耦合机理进行深入认识，对促进我国未来的压电陶瓷无铅化进程具有重要的理论意义和现实意义。

压电陶瓷是一种重要功能材料，广泛应用在各种电子信息产品中。目前大量使用的有毒有害的含铅的锆钛酸铅体系压电陶瓷已经不适应日益提高的环保要求。本项目研究了多元系铌酸钾钠基无铅压电陶瓷的制备技术及其对显微结构与性能的影响。通过引入新组元探索高性能多元系KNN基无铅压电陶瓷的配方，并利用添加低熔点助烧剂降低多元系KNN基陶瓷的烧结温度，从而避免碱金属挥发导致的不致密和化学成分偏差等问题。在获得可低温烧结高性能多元系KNN基压电陶瓷材料的基础上，研究具有高择优取向度KNN基无铅压电陶瓷的RTGG制备技术，制备出具有较高织构度的KNN-LT,KNN-LN无铅压电陶瓷。本项目的开展促进无铅压电陶瓷实用化的发展，对于促进我国未来的压电陶瓷无铅化进程具有重要的指导意义。