铌酸盐铋层状高温压电陶瓷的电-光性能调控及其机理研究

Multifunctional ceramic materials, which possess high Curie temperature, good piezoelectric properties as well as better luminescence performances, have extensive application prospects in industrial fields. Niobate bismuth layer structure piezoelectric ceramics （MBi2Nb2O9, M=Sr, Ca, Ba, Na0.5Bi0.5, K0.5Bi0.5, etc.）have attracted great attentions due to its high Curie temperature, excellent thermal stability, and good luminescence performances after rear earth doping. In this project, the layered piezoelectric materials Re2Ti2O7 (Re=La, Nd, Pr, etc.) with super high Curie temperature will be employed to regulate and control the structure and properties of MBi2Nb2O9 ceramics. Transition elements (Co、Mn、Cr, etc.) doping and atmosphere sintering will also be adopted to further optimize the piezoelectricity of MBi2Nb2O9. The mechanism and effect of Re2Ti2O7 doping on the lattice distortion, domains and lattice defects of MBi2Nb2O9 will be investigated systemically. The luminescence of MBi2Nb2O9–Re2Ti2O7 ceramics will be studied. Based on these results, the relationship of composition-structure-properties of MBi2Nb2O9–Re2Ti2O7 system will be clarified. These research results have important implications for the investigation of theories and industrial applications of bismuth layer-structured piezoelectric ceramics.

具有高居里温度、高压电性能和光致发光性能的多功能陶瓷材料在工业领域里具有广泛的应用前景，铌酸盐铋层状结构压电陶瓷MBi2Nb2O9(M=Ca，Ba，Na0.5Bi0.5等）因具有居里温度高、热稳定好、稀土掺杂可获得较好的发光性能等优点而备受关注。本项目拟以MBi2Nb2O9为对象，采用具有超高居里温度的Re2Ti2O7 (Re=La，Nd，Pr等)层状结构压电材料对MBi2Nb2O9陶瓷进行结构和性能调控，并利用过渡族金属元素Co、Mn、Cr等掺杂和气氛烧结工艺进一步提高其压电性能；研究Re2Ti2O7对MBi2Nb2O9陶瓷的晶格畸变、电畴、缺陷影响规律及机理，在此基础上，进一步研究MBi2Nb2O9–Re2Ti2O7体系材料的发光规律，阐明其组成-结构-性能之间的关系，研究结果对铋层状压电材料的基础理论研究和工业应用都具有重要的意义。

本项目主要以铌酸盐铋层状高温压电陶瓷材料为研究体系，对陶瓷材料的制备工艺、显微结构、电学性能以及发光性能进行了系统研究。采用传统固相反应法制备了Na0.5Bi2.5Nb2O9和CaBi2Nb2O9两种体系的陶瓷材料，通过离子掺杂方法对陶瓷材料的结构和性能进行调控，以寻求提高综合性能的最优组分。通过XRD、SEM、Raman光谱、XPS等多种表征技术研究材料的显微结构和组分价态。通过测量介电温谱、压电常数、电滞回线以及复阻抗谱，研究了介电、压电、铁电以及电导等综合电学性能。结合分析离子掺杂对晶体结构、缺陷形成、电学性能的影响，探明了组分-结构-性能的关系。结果表明，适量离子掺杂能够使陶瓷样品的铁电和压电性能显著提高，其中的微观机理是掺杂离子通过改变晶相结构和晶粒尺寸，并减少缺陷形成，从而提高极化强度，增强压电活性，并降低漏导损耗。同时，还研究了稀土离子掺杂陶瓷材料的上转换荧光发光特性，探索了发光性能的影响因素及其作用机制，为铌酸盐铋层状压电材料在荧光方面的应用提供理论基础。此外，本项目还对钽（铌同族元素）酸盐铋层状高温压电陶瓷进行了扩展研究。用传统固相法制备Na0.5Bi2.5Ta2O9铋层状压电陶瓷材料，系统研究了离子掺杂和烧结工艺改进对其显微结构以及电学性能的影响。通过组分调节和工艺优化大幅提升了材料的综合电学性能，并揭示了微观机制，为铌酸盐铋层状压电体系的研究提供了重要参考价值。本项目的成果将促进铌酸盐铋层状压电材料及其相关材料体系的进一步研究和应用，并且对基于高居里温度压电材料的光-电多功能材料的发展具有积极作用。