中文摘要：

采用传统固相法制备Na0.25K0.25Bi2.5Nb2O9＋x Er（NKBN–x Er,0≤x≤0.06）铋层状无铅压电陶瓷,研究了不同Er3＋掺杂量对NKBN–x Er陶瓷显微结构、电学性能及上转换荧光性能的影响。结果表明：所有样品均为单一的铋层状结构;随着Er3＋掺杂量x从0增加到0.06,样品的晶粒尺寸逐渐增大,Curie温度TC升高,适量的Er3＋掺杂能提高陶瓷的压电性能;电导率与温度的关系在高温区域,热激活氧空位二级电离电子电导起主导作用;在980 nm激光激发下,所有样品在513～570和644～679 nm处可观察到绿光和红光发射峰,分别对应于Er3＋的2H11/2→4I15/2、4S3/2→4I15/2和4F9/2→4I15/2能级跃迁。当x=0.02时,电学性能最佳：压电常数d33=22 p C/N,介电损耗tanδ=0.38%,品质因子Qm=2 324,且样品均具有良好的荧光性能,表明该组分陶瓷可作为高温应用光—电多功能材料。

英文摘要：

Na0.25K0.25Bi2.5Nb2O9＋xEr（NKBN-xEr, 0≤x≤0.06） bismuth layered structure lead-free piezoelectric ceramics were prepared by a conventional solid-state reaction method. The microstructure, electrical and up-conversion properties of NKBN-xEr ceramics were investigated. The results show that all the samples possess a single bismuth layered structure. The average grain size and the Curie temperature Tc of samples increase with increasing Er3＋ contents. The piezoelectric properties of the ceramics can be optimized by the addition of a proper content of Er3~. The variation of electrical conductivities with temperature was also analyzed, revealing the dominating conduction from the second ionization from oxygen vacancies at high temperatures. Green or red emissions peaks at 513-570 nrn and 644-679 nm for all the compositions appear under an excitation of 980 nm laser, which are attributed to the energy level transitions 2H11/2-4/15/2, 4S3/2-4/15/2 and 4F9/2-4/15/2, respectively. The ceramic with x=0.02 has the preferable up-conversion properties and exhibits the optimum electrical properties, i.e., d33=22 pC/N, tanδ=0.38 %, and Qm=2 324, indicating that this ceramic can be suitable for high-temperature optical-electrical multifunctional applications.