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

• Published in: Journal of solid state chemistry Vol. 228; pp. 153 - 159
• Main Authors: Emam, W.I., Mabied, Ahmed F., Hashem, H.M., Selim, M.M., El-Shabiny, A.M., Ahmed Farag, I.S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2015
• Subjects: BOND LENGTHS; Ca-doped zirconia; CALCIUM COMPOUNDS; CATIONS; CERAMICS; CONCENTRATION RATIO; DIELECTRIC MATERIALS; DOPED MATERIALS; Electronic/ionic conductivity; FREQUENCY DEPENDENCE; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IONIC CONDUCTIVITY; LATTICE PARAMETERS; MONOCLINIC LATTICES; PERMITTIVITY; Polymorphic structures; Rietveld refinement; Solid state ceramic method; SOLIDS; TEMPERATURE DEPENDENCE; X-RAY DIFFRACTION; ZIRCONATES; ZIRCONIUM OXIDES; Solid state ceramic method; Rietveld refinement; Electronic/ionic conductivity; Polymorphic structures; Ca-doped zirconia
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2015.03.009

Structural study of Zr1−xCaxO2−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. Forming a high temperature cubic zirconia phase at 1200°C using ceramic solid state method and aliovalent cation. [Display omitted] •Formation the high temperature cubic polymorph of zirconia using Ca-doping.•Solid state ceramic method was used for preparing the cubic Ca-doped zirconia.•Substitution of zirconium by calcium increases the lattice parameters and the bond length.•Ionic to electronic conductivity ratio enhanced considerably as Ca-doping level increases.