ELECTROCHEMICAL STUDY OF SAMARIA AND YTTERBIA STABILIZED ZIRCONIA IN THE LOW-TEMPERATURE RANGE - 400-800-DEGREES-C

Samaria and ytterbia stabilized zirconia are unsuitable for high temperature oxygen cells because of their electronic conductivity. Nowadays lower working temperatures are required and it is of interest to study such solid solutions below 800 degree C. The authors studied sintered (ZRO//2)//1// minus //x(Sm//2O//3)//x and (ZrO//2)//1// minus //x(Yb//2O//3)//x (x equals 0. 08; 0. 12; 0. 15) solid electrolyte cells between 400 and 800 degree C, over partial oxygen pressure from 10** minus **5 to 1 atm. Complex impedance and admittance spectra from 0. 1 Hz to 1 MHz have been plotted. The ionic transference numbers are obtained from a combination of relaxation diagrams and emf measurements. It appears that these materials are essentially ionic below 600 degree C. The proposed equivalent circuit also makes it possible to determine some interfacial characteristics.