Hydrogen permeation through iron membranes of various thicknesses was studied by using the electrochemical permeation technique. The membranes were charged with hydrogen by galvanostatic cathodic polarization in 0.1M NaOH at 25C. The measured build-up and decay permeation current transient was examined. The experimental results revealed that the diffusion apparently increased with decreasing membrane thickness. This result suggested that the hydrogen transport through the membrane was governed mainly by hydrogen trapping at the trap sites present at the grain boundaries. The influence of the passive layer on the hydrogen permeation and its influence upon the evaluation of diffusion and trapping characteristics were considered.

Study of the Electrochemical Permeation of Hydrogen in Iron. H.Addach, P.Berçot, M.Rezrazi, J.Takadoum: Corrosion Science, 2009, 51[2], 263-7