Measurements were performed by using the serial sectioning tracer technique. The lattice diffusion at 1023 to 1473K was found to be described by:

D (m2/s) = 6.3 x 10-6 exp[-243(kJ/mol)/RT]

Grain-boundary diffusion at 923 to 1273K was found to be described by:

D (m3/s) = 1.5 x 10-12 exp[-191(kJ/mol)/RT]

The effects of dislocation pipe-diffusion were observed near to the surface below 973K, and also at deep penetrations above that temperature.

A.F.Smith: Metal Science, 1975, 9[8], 375-8