A multi-scale modeling approach was used to study oxygen diffusion in cubic yttria-stabilized zirconia. Density functional theory methods were used to calculate the activation energies for oxygen migration in various cation environments. These were used, within a kinetic Monte Carlo framework, to calculate the long-term oxygen diffusivities. Simulation results showed that the oxygen diffusivity attained a maximum value at around 0.1mol yttria. This variation in the oxygen diffusivity with yttria mole fraction, and the calculated values of the diffusivity, agreed well with experiment. The competing effects of increased oxygen vacancy concentration and increasing activation energy and correlation effects for oxygen diffusion with increasing yttria mole fraction were responsible for the observed dopant-content dependence of the oxygen diffusivity. A detailed analysis was made of cation dopant-induced correlation effects in order to support this explanation.

Oxygen Diffusion in Yttria-Stabilized Zirconia: a New Simulation Model. R.Krishnamurthy, Y.G.Yoon, D.J.Srolovitz, R.Car: Journal of the American Ceramic Society, 2004, 87[10], 1821-30