KINETIC MONTE CARLO SIMULATION OF CATION DIFFUSION IN YTTRIA-STABILIZED ZIRCONIA

摘要

Yttria-stabilized zirconia (YSZ) is of interest to the aerospace community, notably for its application as a thermal barrier coating. In such an application, the inhibition of oxygen diffusion is a major concern, and this issue has been addressed via molecular dynamics and kinetic Monte Carlo simulation. However, the mechanical integrity of such coatings can be affected by processes involving diffusive motion on the cation lattice. In this work, we perform kinetic Monte Carlo simulations to investigate cation diffusion in YSZ. Using diffusive migration barrier energies from the literature, we obtain diffusivities that are several orders of magnitude smaller than oxygen diffusivities from experiment, or from earlier simulations. We report on the effects on cation diffusivity of cation sublattice vacancy concentration, Y concentration, and temperature, and relate these results to oxygen diffusion in the same materials.