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 210Pb diffusion data, for 347 to 569C, could be described by:

D (cm2/s) = 1.40 x 10-2 exp[-0.982(eV)/kT]

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