Oxygen isotope exchange in doped lanthanum zirconates

Abstract

The interaction between oxygen in the gas phase and La2–xCaxZr2O7–α (x = 0; 0.05; 0.1) with a pyrochlore structure was studied by the isotope exchange method with the gas phase equilibration in the temperature range of 600–900 °C and the oxygen pressure of 1.01 kPa. The oxygen diffusion and oxygen surface exchange coefficients were calculated for the investigated oxides. The rate-determining stage of the oxygen surface exchange kinetics for La1.9Ca0.1Zr2O7–α was found to be different from that for La1.95Ca0.05Zr2O7–α and La2Zr2O7–α. The influence of the calcium content in La2–xCaxZr2O7–α (x = 0; 0.05; 0.1) oxides on the heterogeneous exchange rates and oxygen tracer diffusion coefficients were discussed.