Samples of polycrystalline material were studied at 750 to 1050C by using a groove and stain technique. It was shown that the Fisher model for grain boundary diffusion accurately described the data when an infinite source was assumed. It was found that the grain boundary diffusivity was described by:

D (cm2/s) = 4.0 x 1015 exp[-2.09(eV)/kT]

assuming a grain boundary width of 0.5nm.

P.H.Holloway, T.Abrantes: Journal of Vacuum Science and Technology A, 1989, 7[3], 1573-8