The permeation behavior of H in pure Al was investigated at 625 to 773K by using a gas permeation technique. The H permeation rate was strongly affected by the surface conditions where the H was introduced into the sample. The presence of an oxide layer on the surface made it difficult to permeate H through the sample. The oxide layer was reduced by H during permeation runs at temperatures above 700K, and this resulted in higher H permeation rates during subsequent permeation runs. On the other hand, the H permeation rate was decreased by temporary poisoning of the surface.

Effect of Surface on Hydrogen Permeation through Pure Aluminium. Y.Furuya, A.Takasaki, M.Koga, T.Kino: Materials Science Forum, 2000, 331-337, 1665-70