An investigation was made of the H permeation of Pd/V-15Ni/Pd and Pd-25Ag/V-15Ni/Pd-25Ag alloy composite membranes with about 40μm and 1mm thickness at 423 to 673K. The H permeation of Pd-25Ag/V-15Ni/Pd composite membranes with about 40μm thickness was also examined. There were 2 directions for the H permeation of Pd-25Ag/V-15Ni/Pd composite membranes. Higher permeation flux was obtained in the Pd-25Ag/V-15Ni/Pd composite membrane when the Pd-25Ag over-layer was at the up-stream side and the Pd over-layer was at the down-stream side. Overall H diffusion coefficients of the composite membranes were independent of the permeation pressure and over-layer, while H permeation flux had strong dependence on the over-layer composition and sequence. Membrane thickness and over-layer had profound effects on H permeation of composite membranes.

Hydrogen Permeation and Diffusion of Metallic Composite Membranes. Y.Zhang, R.Maeda, M.Komaki, C.Nishimura: Journal of Membrane Science, 2006, 269[1-2], 60-5