Simulation of grain-boundary diffusion in ceramics by kinetic Monte Carlo

We show how methods based on an encounter model for diffusion can be used to simulate the grain-boundary diffusion coefficients in ceramics. Boundaries in NiO and Al2O3 are used as examples of the method. The anisotropy of diffusion in boundaries (expected from the picture of a grain boundary as a dislocation array and seen in experiment) is well reproduced. The calculated activation energies for grain-boundary diffusion are inreasonable agreement with experiment. Problems in comparing the simulations with experiments on polycrystals are discussed.