(Na1/2Bi1/2)TiO3-(Na1/2Bi1/2)(Zn1/3)Nb2/3)O3无铅压电陶瓷的介电特性研究  

Study of Dielectric Properties of(Na_(1/2)Bi_(1/2))TiO_3-(Na_(1/2)Bi_(1/2))(Zn_(1/3)Nb_(2/3))O_3 Lead-free Piezoelectric Ceramics

作　　者：杨桂华[1] 周昌荣[2] 刘心宇[2] 

机构地区：[1]桂林工学院电子与计算机系,桂林541004 [2]桂林电子科技大学信息材料科学与工程系,桂林541004

出　　处：《人工晶体学报》2008年第2期399-402,375,共5页Journal of Synthetic Crystals

基　　金：广西自然科学基金(No.0447092)

摘　　要：采用固相合成法制备了(1-x)(Na1/2Bi1/2)TiO3-x(Na1/2Bi1/2)(Zn1/3Nb2/3)O3(简写为(1-x)NBT-xNBZN)无铅压电陶瓷。研究了该体系陶瓷晶体结构、弥散相变特征与介电弛豫行为。X射线衍射分析表明,所研究的组成均能够形成纯钙钛矿(ABO3)型固溶体。当x≥0.5%摩尔分数时,该体系陶瓷具有三方、四方共存的晶体结构。材料的介电常数-温度曲线显示陶瓷具有两个介电反常峰Tf和Tm。修正的居里-外斯公式较好的描述了陶瓷弥散相变特征,弥散指数随x的增加而增加。x≤0.5%摩尔分数的陶瓷仅在低温介电反常峰Tf附近表现出明显的频率依赖性,随x的增加,陶瓷材料在室温和低温介电反常峰Tf之间都表现出明显的频率依赖性。根据有序-无序转变和宏畴-微畴转变理论探讨了该体系陶瓷介电弛豫特性的机理。The dielectric properties and relaxation of （1-x）（Na1/2Bi1/2）TiO3-x（Na1/2Bi1/2）（Zn1/3Nb2/3）O3 lead-free piezoelectric ceramics were investigated. X-ray diffraction showed that all compositions formed a solid solution with perovskite-type structure. The （1-x）NBT-xNBZN ceramics had a morphotropic phase boundary（MPB） between rhombohedral and tetragonal locates at x≥0.5mo1%. The temperature dependence of dielectric constant εr revealed that the solid solution exist two dielectric abnormal peaks Tf and Tm. The thermal variation of the permittivity was well described by a law 1/ε- 1/εm = C（ T-Tm ） γ and the diffuse coefficient y value increased with increasing concentration of x. The samples with x≤0.5mol% exhibited obvious frequency dependence only near Tf and the samples with x ≥2.0mol% exhibited obvious frequency dependence between room temperature and Tf. The mechanism of relaxor behavior was also discussed according to the order-disorder transition and the macro-domain to micro-domain transition theory.

关 键 词：钛酸铋钠 无铅压电陶瓷 介电性能 弛豫特性 

分 类 号：TM282[一般工业技术—材料科学与工程]