The effect of a high intercrystalline content upon H activity and transport was studied. It was found that nanocrystalline material exhibited a greater electrocatalytic activity as compared with cold-worked, fine-grained or fully annealed Ni electrodes. A further investigation was made of the transport behavior of H in order to determine the H diffusivities and apparent concentrations as a function of the intercrystalline content. Electrolytic charging of H was carried out on Ni bi-electrodes in an electrochemical double cell. Permeated H was detected in Ni membranes, of identical thickness, in the order: nanocrystalline, fine-grained, monocrystalline. The diffusivities were equal to 4.73 x 10-9, 6.52 x 10-10 and 2.02 x 10-10cm2/s in nanocrystalline, fine-grained and monocrystalline material, respectively.

The Influence of Intercrystalline Defects on Hydrogen Activity and Transport in Nickel. D.M.Doyle, G.Palumbo, K.T.Aust, A.M.El-Sherik, U.Erb: Acta Metallurgica et Materialia, 1995, 43[8], 3027-33