Fisher model of intercrystalline diffusion was refined based upon an analysis of previously obtained results of emission Mössbauer studies of grain boundaries. It was shown that under conditions of dominating intercrystalline diffusion, the existence of monatomic near-boundary layers of equilibrium composition should be taken into account. It was found that the allowance for these layers did not change the expressions for the distribution of the concentration of the diffusing impurity in a polycrystal in the case of a type-B kinetic regime, whereas in the type-C regime the corresponding expressions changed somewhat. The technique that was used previously for the determination of parameters of grain-boundary diffusion and segregation, which was based upon the results of emission Mössbauer investigations of grain boundaries, was modified; the application of the new approach was demonstrated on the example of processing data of Mössbauer investigations of grain boundaries in polycrystalline Nb at 119mSn nuclei.

Model of Grain-Boundary Diffusion with Allowance for Near-Boundary Layers of Equilibrium Composition. V.V.Popov: The Physics of Metals and Metallography, 2006, 102[5], 453-61