(449am) Composite Palladium Membrane Robust below 573 K Prepared with Sputtering Technique

For the last two decades, several ways such as electroless-plating, electroplating, sputtering and chemical vapor deposition have been proposed to prepare a composite type of thin palladium membrane, whereby improving the hydrogen permeability significantly. However, it has been pointed out that the robustness of palladium composite membrane itself especially at low temperatures is not enough for practical use. Thin palladium film is well known to expand and contract by hydrogen absorption and desorption particularly below 573K, that is, the critical temperature, leading to peel-off from its support and crack.

In this study, an approach is explored to avoid such occurrences of defects. One is to prepare a palladium alloyed membrane. The other is to prepare a double-layer palladium membrane, in which between a palladium film and a porous support a metallic interlayer to depress a deformation is introduced. Pd-Cu alloyed and Pd/Pt layered membranes supported on porous alumina tube are successfully completed employing sputtering technique. Both membrane tubes could show a higher hydrogen permselectivity and a robustness even in the range of 473-573 K.