ATOMIC LEVEL SIMULATION OF OXYGEN DIFFUSION IN YTTRIA-STABILIZED ZIRCONIA

摘要

We have used molecular dynamics to study the dependence of oxygen diffusion in bulk yttria-stabilized zirconia on the yttria content. Oxygen diffusion occurs by the vacancy mechanism, and the diffusion coefficient showed a peak at 8 mole% yttria. The activation energy for oxygen diffusion varied from about 0.6 to 1.0 eV depending on the yttria content, in good agreement with experimental observations. The results indicate that the oxygen vacancy prefers to bind to Zr~(4+) rather than to Y~(3+), and this defect-dopant interaction determines the composition dependence of the oxygen diffusion coefficient.