Measurements were made of the diffusivity of B in nanocrystalline Fe. It was shown that the B diffused slower in the grain boundaries than in the lattice. Even though the lattice diffusion was faster than grain-boundary diffusion, the grain-boundary diffusion coefficient was easily obtained. Overall, the data could be described by:

D (m2/s) = 1.7 x 10-11exp[-0.59(eV)/kT]

H.J.Höfler, R.S.Averback, H.Gleiter: Philosophical Magazine Letters, 1993, 68[2], 99-105