Abstract
The diffusion of a sorbate in a solid body bisected by a narrow straight grain boundary has been simulated using a combination of the so-called floating random walk Monte Carlo technique and a modified technique of that sort, particularly applicable to the study of random walks inside narrow grain boundaries. The results have been compared to the published solutions obtained from deterministic methods. Complex composite processes involving simultaneous bulk, grain boundary, and surface diffusion have been simulated as well, using the techniques so developed, so as to show that the computations are quite feasible, even though at this point the results cannot always be verified by comparison to known solutions.