PREPARATION AND CHARACTERIZATION OF SOLED ELECTROLYTE CERAMIC OF SrCe_(1-x)Zr_xO_3 DOPED Y_2O_3 AS PROTONIC CONDUCTOR AT HIGH TEMPERATURE

摘要

These ceramics with formula Sr(Ce_(1-x)Zr_x)_(0.9)Y_(0.1)O_(2.95) (x=0, 0.25, 0.5, 0.75 and1) prepared by solid-state reaction. Powder X-ray diffraction analysis of the samples showed single phase with orthorhombic perovskite type structure except the sample with x=0.75. The samples exhibited the highest relative density of the sintered pellets were 97.88% measured by the geometry method. The electric conductivity of samples was then investigated by impedance spectroscopy using high frequency response analyzer (HFRA). The impedance spectra were recorded for frequencies in the range of 1 Hz to 10 Mhz in the temperature range of 400°C to 900°C in wet and dry nitrogen. The oxides showed the highest conductivities with a value 7.14 x 10~(-3) Scm~(-1) in wet nitrogen and 8.01 x 10~(-3) Scm~(-1) in dry nitrogen both at 900°C. Emf measurements were carried out using the samples as a solid electrolyte in hydrogen concentration cell. The emf of hydrogen concentration cell exhibited the highest protonic conduction in the sample with proton transport numbers with a value 0.78 at 800°C and 900°C.