A位非化学计量比对KNN-BSC陶瓷微结构及电学性能的影响  

Effects of A-site non-stoichiometry on the microstructure and electrical properties of KNN-BSC ceramics

作　　者：程花蕾[1] 严云云[1] 肖琳莹 李艳阳 陈壮壮 CHENG Hua-lei;YAN Yun-yun;XIAO Lin-ying;LI Yan-yang;CHEN Zhuang-zhuang(Shaanxi Key Laboratory of Phytochemistry,College of Chemistry and Chemical Engineering,Baoji University of Arts and Sciences,Baoji 721013,Shaanxi,China)

机构地区：[1]宝鸡文理学院化学于化工学院,陕西省植物化学重点实验室,陕西宝鸡721013

出　　处：《宝鸡文理学院学报（自然科学版）》2022年第4期35-41,共7页Journal of Baoji University of Arts and Sciences(Natural Science Edition)

基　　金：国家自然科学基金青年项目(21501007);陕西省科技厅自然科学项目(2019JQ-897);国家级大学生创新创业项目(2018XJ038;201827014)。

摘　　要：目的 研究A位非化学计量比对具有两相共存结构的KNN陶瓷结构和性能的影响,对于KNN基无铅压电陶瓷的设计具有重要的指导意义。方法 采用固相法制备0.985K_(0.5)+xNa_(0.5)+xNbO_(3)-0.015Bi(Sc0.75Co0.25)O3(简称K_(0.5)+xN_(0.5)+xN-BSC,x=0,0.002 5,0.005,0.007 5,0.01,0.012 5,0.015,0.02 mol%)陶瓷。研究了K+,Na+的含量对K0.5+xN0.5+xN-BSC陶瓷密度、微观结构、相结构和电性能的影响。结果 K_(0.5)+xN_(0.5)+xN-BSC陶瓷的密度随烧结温度的升高先增大后减小,1 170℃为各组陶瓷的最佳烧结温度,且x=0.007 5时K_(0.5)+xN_(0.5)+xN-BSC陶瓷密度最大,ρmax=4.37 g/cm^(3)。XRD结果表明具有不同K+,Na+含量的K_(0.5)+xN_(0.5)+xN-BSC陶瓷均为纯钙钛矿结构,随K^(+),Na^(+)含量增加,陶瓷的相结构由正交四方混合相转变为四方相。SEM结果表明K0.5+xN0.5+xN-BSC陶瓷晶粒尺寸随着x含量的增加而增加。当x=0.007 5时,K_(0.5)+xN_(0.5)+xN-BSC陶瓷颗粒呈规则立方状,尺寸均匀,排列致密。电性能测试结果表明,K_(0.5)+xN_(0.5)+xN-BSC陶瓷的介电性能、压电性能随x含量的增大均呈现出先升高后降低的趋势。当x=0.007 5,烧结温度为1 170℃时,K_(0.5)+xN_(0.5)+xN-BSC陶瓷电性能较好:TC=360℃,εr=5 860(100 kHz),tanδ<5%(100 kHz),d33=190 pC/N,Kp=41%。结论 随着钾钠比值的增大,陶瓷趋于形成更稳定的四方相结构,陶瓷的电性能指标先升高后降低。Purposes-To investigate the importance of the remarkable influence of A-site non-stoichiometry on the structural and electrical properties of KNN-based ceramics for guiding the design of KNN-based lead-free ceramics. Methods-Lead-free piezoelectric ceramics of 0.985K_(0.5)+xNa_(0.5)+xNbO3-0.015Bi(Sc0.75Co0.25)O3(abbreviated as K_(0.5)+xN_(0.5)+xN-BSC, x=0, 0.002 5, 0.005, 0.007 5, 0.01, 0.012 5, 0.015, 0.02 mol%) were prepared by solid-state reaction. The effects of K+and Na+contents on the density, microstructure, phase structure, and electrical properties of K_(0.5)+xN_(0.5)+xN-BSC ceramics were studied. Result-The density-sintering temperature results showed that the density of K_(0.5)+xN_(0.5)+xN-BSC ceramics firstly increase and then decrease with the increase of the sintering temperature. The best sintering temperature for each group of ceramics is 1 170 ℃. When x=0.007 5, the density of ceramics show the maximum value, namely, 4.37 g/cm^(3). The XRD results showed that the K_(0.5)+xN_(0.5)+xN-BSC ceramics with different K+and Na+contents are all pure perovskite structure and the structure changes from the coexistence of rhombohedral-tetragonal phase to tetragonal phase. The SEM results showed that the grain size of K_(0.5)+xN_(0.5)+xN-BSC ceramics increased with the increases of the x contents. When x=0.007 5, the particles are regular cubic, featuring uniform size and dense arrangement. The results of dielectric and piezoelectric tests showed that the dielectric and piezoelectric properties of K_(0.5)+xN_(0.5)+xN-BSC ceramics firstly increase and then decrease with the increase of the x contents. When x=0.007 5, the K_(0.5)+xN_(0.5)+xN-BSC ceramics show good property that TC=360 ℃, εr=5 860, tanδ<5%(100 kHz), d33=190 pC/N, Kp=41% at the sintering temperature of 1 170 ℃. Conclusion-The ceramics tended to form stable tetragonal structure with the increase of K/Na ratio, and the electrical properties of the ceramics increased first and then decreased.

关 键 词：铌酸钾钠 相结构 微观形貌 电性能 

分 类 号：TB34[一般工业技术—材料科学与工程]