The hydrogen flux degradation in hydrogen permeation tests of Pd/Nb30Ti35Co35 (at.%)/Pd composite membranes was experimentally investigated at temperatures from 400 to 650 °C. The hydrogen fluxes through the Pd/Nb30Ti35Co35/Pd membranes during isothermal long-term hydrogen permeation tests above 500 °C exhibit two hydrogen-flux-decline steps. The aggregation of the Pd-catalytic layer and the boundary layer formed between Pd and Nb30Ti35Co35 due to interdiffusion were experimentally confirmed contributing to the degradation of the hydrogen flux through the Pd/Nb30Ti35Co35/Pd membrane. Modelling work was carried out to reveal and validate the temperature-dependence of the two attributing factors to the degradation of hydrogen permeation flux.
- Hydrogen permeability