Influence of Reversible Hydrogen Doping on the Surface of Diffusion Filter Membranes

In this paper the surface of diffusion filter membranes of alloy Pd–5.3 at %–In–0.5 at % Ru is studied by atomic force microscopy. This alloy is in demand in the diffusion separation processes of high-purity hydrogen. The surface of membranes is studied before and after hydrogenation. Prior to hydrogenation, it is determined that the surface structure of the membrane alloy contains regions of a local increase in hardness. These regions are surrounded by a significant dislocation density. It is found that reversible hydrogen doping of the membrane alloy both from the gas phase and by the electrochemical method do not eliminate the presence of such regions. The dispersion of the surface structure of diffusion filter membranes is revealed and a large degree of surface changes is determined during electrochemical hydrogenation compared to gas-phase hydrogenation.