Bi0.5(Na0.82K0.18)0.5TiO3-BiFeO3无铅压电陶瓷的介电特性  

Dielectric Behavior of Bi_(0.5)(Na_(0.82)K_(0.18))_(0.5)TiO_3-BiFeO_3 Lead-free Piezoelectric Ceramics

作　　者：周沁[1] 杨桂华[2] 周昌荣[1] 

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

出　　处：《人工晶体学报》2009年第2期358-361,377,共5页Journal of Synthetic Crystals

基　　金：广西自然科学基金(No.0447092);广西信息材料重点实验室主任基金

摘　　要：采用固相反应法制备了系列(1-x)Bi0.5(Na0.82K0.18)0.5TiO3-xBiFeO3(BNKT-BFx)陶瓷。研究了该陶瓷在室温至500℃范围内的介电性能。结果表明:该陶瓷的介电温谱与典型弛豫铁电体的特征不同,存在两个介电反常峰和一个介电损耗峰,只在低温介电反常峰温度附近具有明显的介电常数的频率依赖性,居里温度随频率增加基本不变。首次提出了弛豫铁电体分为本征弛豫和非本征弛豫铁电体的理论。通过分析极化前和极化后陶瓷的介电温谱,发现该体系低温介电反常峰温度附近的介电频率依赖性为空间电荷和缺陷偶极子极化引起的非本征弛豫。The series of （1-x）Bi0.5（Na0.82K0.18）0.5TiO3-xBiFeO3（BNKT-BFx） Lead-free piezoelectric were prepared by a conventional solid state reaction method,the dielectric properties of the system between room temperatue and 500 ℃ were investigated.The results indicate that there are two abnormal dielectric peaks and a dielectric loss peak with the increasing temperature. The dielectric constant near the temperauture of low temperature abnormal peak exsist obvious frequency dependence, and Curie temperature change little as frequency increasing, which is different from the characteristics of typical relaxor ferroelectrics. The thoery that relaxor ferroelectrics were divided into the intrinsic relaxor ferroelectrics and extrinsic relaxor ferroelectrics has been proposed. It was found that the frequency dependence near the temperature of low temperature dielectric abnormal peak was extrinsic relaxor which was created by space charges and defects dipole by analzing the εr-T curves of poled and unpoled samples.

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]