The isotope effect for diffusion through single-crystal membranes (6.3 x 10-3cm-thick) was investigated by using the permeation time-lag technique. It was found that the H/D diffusivity ratio (table 99) decreased markedly as the temperature was decreased to below 460K. The H diffusivity at 367.2K was equal to 1.19 x 10-8cm2/s.

Reduction of the Isotope Effect in Diffusion of Hydrogen in Nickel at Low Temperatures. Y.Ebisuzaki, M.O’Keeffe: Journal of Chemical Physics, 1968, 48[4], 1867-8