Phase Transitional Behavior and Dielectric Properties of (Ba,Ca)(Ti,Zr)O₃–Bi(Zn,Zr)O₃ Lead-Free Ceramics

Abstract

The (1-x)(Ba_0.98Ca_0.02)(Ti_0.95Zr_0.05)O₃–xBi(Zn_0.5Zr_0.5)O₃ [BCZT–xBZZ, x = 0.005–0.06] lead-free solid solution ceramics were synthesized by a conventional solid state reaction method. The effect of Bi(Zn_0.5Zr_0.5)O₃ addition on the crystal structure, microstructure, relaxor behavior and dielectric properties of the (Ba_0.98Ca_0.02)(Ti_0.95Zr_0.05)O₃ ceramics has been studied. X-ray diffraction shows that all the ceramics possess a single phase of perovskite structure. The BCZT–xBZZ ceramics change from tetragonal phase to pseudocubic phase with the content of BZZ increasing. Moreover, the grain size is affected by BZZ addition. The BCZT–xBZZ ceramics become considerably dense with the proper amount of BZZ introduction. The relative permittivity ϵ_r and loss tangent tanδ vary with the increasing BZZ content. Temperature dependence of the dielectric properties indicates that as the concentration of BZZ increases, the BCZT–BZZ solid solution ceramics exhibit more relaxor-like behavior. Furthermore, the BCZT–xBZZ ceramics exhibit low dielectric loss and excellent dielectric temperature stability in a wide temperature range, which indicates a potential application in devices under comparably high-temperature environment.

Keywords:

• Ceramics
• sintering
• dielectric properties
• diffusion
• phase transition

Funding

This work is supported by the National Key Project for Basic Research of China (Nos. 2012CB619406 and 2013CB632900), International Science & Technology Cooperation Program of China (No. 2013DFR50800), National Natural Science Foundation of China (Nos. 61137004, 61275181 and 61311120086), NSAF (Nos. U1330119 and U1330120).