Bulk oxygen self-diffusion in yttria-stabilised zirconia was investigated using tracer diffusion experiments and molecular dynamics simulations as a function of yttria content. Experimentally, 18O tracer diffusion was measured at 650 to 1200K for an yttria content  of 8 to 24mol%Y2O3, using gas-phase exchange of the stable isotope 18O, and secondary ion mass spectrometry. For a given temperature, the diffusivity was highest for yttria-stabilised zirconia containing 10mol% yttria. The activation enthalpy for diffusion was 0.8 to 1.0eV, regardless of the yttria content. The diffusion process was simulated using molecular dynamics and various potentials. The oxygen diffusion coefficient was found to be of similar magnitude to the experimental value, and also exhibited a similar concentration dependence; with a maximum for yttria-stabilised zirconia containing 10mol% yttria. The calculated activation enthalpies of oxygen transport were close to the values observed experimentally.

Oxygen Diffusion in Yttria Stabilised Zirconia - Experimental Results and Molecular Dynamics Calculations. Kilo, M., Argirusis, C., Borchardt, G., Jackson, R.A.: Physical Chemistry Chemical Physics, 2003, 5[11], 2219-24