Phase evolution, microstructure, thermal stability and conductivity behavior of (Ba1-xBi0.67xK0.33x)(Ti1-xBi0.33xSn0.67x)O3 solid solutions ceramics

(Ba1-xBi0.67xK0.33x)(Ti1-xBi0.33xSn0.67x)O-3 (BBKTBS) [x = 0.02, 0.04, 0.06, 0.08, 0.1 and 0.12] solid solutions ceramics were fabricated via a traditional solid phase reaction method. X-ray diffraction and Raman spectra confirmed that the ceramics transform from tetragonal phase (x <= 0.04) to pseudo-cubic phase (0.06 <= x <= 0.12). When x = 0.1, the ceramic exhibited the optimum dielectric properties with large relative permittivity epsilon(r)(similar to 1850), low tan delta (<2%) in temperatures from 20 degrees C to 200 degrees C and good thermal stability Delta epsilon/epsilon(25 degrees C) (<=+/- 15%) from -55 degrees C to 160 degrees C. The conductivity behavior of ceramic at high temperatures shown that the basic mechanisms of conduction and relaxation processes were thermal activation, and oxygen vacancies might be the ionic charge transport carriers. (C) 2018 Elsevier B.V. All rights reserved.