(1-x)KNN-xNKBT无铅压电陶瓷的结构及其电性能研究

摘要

采用传统固相法制备了(1-x) K0.5Na0.5NbO3-x(Na0.8K0.2)0.5Bi0.5TiO3(x=0-5％)无铅压电陶瓷,研究了(Na0.8K0.2)Bi0.5TiO3的不同引入量对其物相结构、显微形貌、介电性能以及压电性能的影响.结果表明:所有样品都具有钙钛矿结构；随着x的增加,室温下样品从正交相逐渐向四方相过渡并且居里温度向低温方向移动,样品的压电常数d33与机电耦合系数kp均先升高后降低.该体系多晶型转变PPT位于2％≤x≤3％,当x=3％时,样品的压电性能达到最佳,其中:d33=189pC/N,kp=41％,Qm=96,tanδ=0.028.%In this paper, (1-x)K0.5Na0.5Nb03-x (Na0.8K0.2)0.5Bi0.5TiO3 (x=0-5%) lead-free piezoelectric ceramics were synthesized by solid-state reaction method. The effects of the content of (Na0.8K0.2)0.5Bi0.5TiO3 on the phase, microstructure, dielectric and piezoelectric properties of the samples were investigated. The results show that all samples possess perovskite structure. With the increasing amount of (Na0.8K0.2)0.5Bi0.5TiO3, the phase structure of the samples at room temperature changes from orthorhombic symmetry to tetragonal symmetry and both the piezoelectric constant d33 and planar coupling factor kp of the samples increase first and then decrease while Curie temperature decreases gradually. A polymorphic phase transition (PPT) from orthorhombic to tetragonal symmetry occurs in the composition range of 2%≤x≤3% in this system and the ceramic sample in the composition of x=3% owns peak piezoelectric properties (d33=189pC/N, kp=41%, Qm=96, tanδ=0.028).