Peculiarities of ionic transport of oxygen vacancy conducting superionic ceramics (original) (raw)

The powder of Zr0.92Y0.08O2 (YSZ), Ce0.9Gd0.1O 2−δ (GDC) and Sm0.15Ce0.85O 2−δ (SDC) compounds from the company Fuel Cell Materials were used for sintering of ceramic samples in air at temperature T = 1673 K. The surface of the prepared ceramics was studied by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Results of the performed XPS investigations revealed that cerium exists as Ce 3+ and Ce 4+ in both the Ce0.9Gd0.1O 2−δ and Sm0.15Ce0.85O 2−δ ceramics. XPS spectra of O 1s of all the investigated materials demonstrated two peaks corresponding to oxygen O(1) in crystal lattice and to adsorbed oxygen O(2). Measurements of complex impedance, electric conductivity, dielectric permittivity, and tan δ of dielectric losses were carried out in frequency range 10 6 -1.2·10 9 Hz at temperatures ranging from 300 K to 700 K. Relaxation dispersion of the electric parameters has been found for all the compounds. The dispersion is caused by the oxygen vacancy (V O •• ) transport in grains of the ceramic samples.