The measurement of the so-called true grain boundary diffusivity in the C kinetic regime was illustrated for Ag self-diffusion. It was noted that there existed a transitional regime in which classical analysis of grain-boundary diffusion profiles (assuming B-type or C-type conditions) was inapplicable. An alternative method for treating this regime was tested which permitted the determination of both the true grain-boundary double products, and the true grain-boundary diffusion coefficients, from experimental profiles. At 423 to 803K, the true grain-boundary diffusivity of Ag could be described by:

D (cm2/s) = 1.26 x 10-1 exp[-0.87(eV)/kT]

P.Gas, D.L.Beke, J.Bernardini: Philosophical Magazine Letters, 1992, 65[3], 133-9