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]

The Simultaneous Diffusion of Pb2+ and Cd2+ in Purified NaCl Single Crystals. J.L.Krause, W.J.Fredericks: Journal of Physics and Chemistry of Solids, 1971, 32[12], 2673-84