Controlling polymorphic structures and investigating electric properties of Ca-doped zirconia using solid state ceramic method

摘要

Structural study of Zr(1-x)CaxO(2-x) samples with x=0.01-0.15 were prepared using solid state ceramic method. X-ray diffraction analysis revealed a mixture of the high temperature phase and the monoclinic one for the samples with x <= 0.05. On the other hand, the formation of a single high temperature cubic phase was observed within a concentration range of x=0.06-0.10. At concentrations higher than 0.10 the calcium zirconate phase was observed besides the dominant high temperature one. Rietveld refinement of the single phase data clearly revealed, that substitution of zirconium by calcium increases both the lattice parameters as well as the tetrahedral bond length. Ionic to electronic conductivity ratio enhanced considerably as Ca-doping level ascends. The dielectric constant shows strong temperature dependence at lower frequencies. The dielectric loss factor increases rapidly with the increase in temperature at lower frequencies, while decreases with the increase in frequency at higher temperatures. The ionic conduction is considered as the dominant process at higher temperatures. (C) 2015 Elsevier Inc. All rights reserved.