The simultaneous diffusion of 210Pb and 109Cd into ion-exchange purified single crystals was studied by using the serial sectioning radiotracer technique. It was found that the 109Cd diffusion data, for temperatures ranging from 347 to 569C, could be described by:

D (cm2/s) = 3.57 x 10-3 exp[-0.857(eV)/kT]

J.L.Krause, W.J.Fredericks: Journal of the Physics and Chemistry of Solids, 1971, 32[12], 2673-84