The diffusion of Pb2+ ions in single-crystal KCl was studied at 200 to 475C. A radioactive tracer technique was used which involved diffusion from a deposited surface layer of PbCl2 or diffusion from PbCl2 vapor. The diffusion of Pb in pure KC1 obeyed:

D(cm2/s) = 1.02 x 10-3 exp[-23300/RT]

F.J.Keneshea, W.J.Fredericks: The Journal of Chemical Physics, 1963, 38[8], 1952-8