铌酸铋锶基铋层状结构复相陶瓷的介电弛豫性能  

Dielectric Relaxation Properties of Strontium Bismuth Niobate-based Bismuth Layer Structure Composite Ceramics

作　　者：周康[1] 杜慧玲[1] 郝星辰 姚淼[1] 

机构地区：[1]西安科技大学材料科学与工程学院,西安710054

出　　处：《硅酸盐学报》2016年第6期799-805,共7页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金(51372197);陕西省重点科技创新团队(2014KCT-04);陕西省国际科技合作重点项目(2012KW-10)资助

摘　　要：采用分步固相烧结工艺制备(1–x)SrBi_2Nb_2O_9–xN_(0.5)Bi_(0.5)TiO_3(SBN–NBT)铋层状结构复相无铅压电陶瓷。利用X射线衍射仪、扫描电子显微镜及介电和压电测试系统等对陶瓷样品的相结构、微观形貌和电性能进行表征。结果表明:样品均形成了钙钛矿结构(BLSF)相与铋层状结构相两相共存的复相结构,铋层状结构相随NBT引入量增多由SBN逐渐转变为2层与3层BLSF插层结构相,再转变为3层铋层状相。随着NBT组分增加,相变峰向高温移动,铁电–顺电相变峰值介电常数随之减小,相应的介电峰半高宽弥散度增大,铁电–顺电相变弥散程度增强。当x=0.4时,样品弥散因子γ达到1.95,表现出典型的弛豫铁电体相变特征;当x=0.1时,样品电性能达到最佳值:Curie温度TC、室温介电常数和d33分别达到474℃、177和13 p C/N。（1-x）SrBi2Nb2O9-xNa0.5Bi0.5TiO3（SBN-NBT, x=0.1,0.2,0.3,0.4,0.5） ceramics were fabricated via a step ceramic processing. The crystal structure, microstructure and electrical properties were investigated. The coexisted structures of the bismuth layer structured （BLSF） phase and the perovskite Na0.0Bi0.5TiO3 phase in the ceramics were determined by dielectric spectrum, analysis, X-ray diffraction, scanning electron microscopy, respectively. The phase transition characteristics were investigated. The results show that two-layered SBN forms two-layered and three-layered BLSF inserted layer compounds, and subsequently form three-layered BLSF compounds. The structural, dielectric and piezoelectric properties were analyzed with respect to the influence of the NBT content. The phase transition peaks shift to a high temperature region, the peak value er reduces and the dispersion degree of peak FHWM increases with increasing the NBT content. According to the the dielectric response behaviors, normal ferroelectric-paraelectric phase transition to a relaxor-like behavior occurs when NBT content increases. When x=0.4 and γ=1.95, the sample shows the phase transition characteristics of typical relaxation ferroelectrics. As a result, optimized comprehensive electrical properties are obtained in the 0.9SBN--0.1NBT composition, i.e., Tc=474℃, dielectric constant εr=177 and d33=13 pC/N.

关 键 词：铋层状结构 弥散相变 弛豫铁电体 介电性能 

分 类 号：TQ174[化学工程—陶瓷工业]