The diffusivity was measured by using the grain-boundary grooving method, and coarse-grained specimens. Diffusion anneals were carried out at 1073, 1123 and 1163K. In a H ambient, with a dew-point of 213K, the surface self-diffusivity could be described by:

D (cm2/s) = 1.0 x 105 exp[-228(kJ/mol)/RT]

K.Nii, K.Yoshihara: Transactions of the Japan Institute of Metals, 1979, 20[9], 523-32