The permeabilities and true lattice diffusivities of H and D in the austenitic stainless steel were measured at 472 to 779K by using an ultra-high vacuum monopole gas analyzer system. The activation energies for H and D permeation were essentially equal, at 56.56 and 55.84kJ/mol, respectively. The activation energies for H and D diffusion were also essentially equal, at 48.82 and 48.07kJ/mol, respectively. They reflected true lattice diffusion. Comparison of the permeabilities and true lattice diffusivities indicated isotope ratios of 1.44 and 1.38, respectively. This revealed that the mass effect was confined to diffusivity and was in agreement with the isotope ratio of 1.41 which was predicted by classical theory.

Permeation and Diffusion of Hydrogen and Deuterium in 310 Stainless Steel, 472K to 779K. N.R.Quick, H.H.Johnson: Metallurgical Transactions A, 1979, 10[1], 67-70