Low-temperature H-2 and N-2 transport through thin Pd66Cu34Hx layers

The single gas H-2 and N-2 permeability of a 4 mu m thick dense fcc-Pd66Cu34 layer has been studied between room temperature and 5 10 degrees C and at pressure differences up to 400 kPa. Above 50 degrees C the H-2 flux exhibits an Arrhenius-type temperature dependence with J(H2) = (5.2 +/- 0.3) mol m(-2) s(-1) exp[(-21.3 +/- 0.2) kJ mol(-1)/((RT)-T-.)]. The hydrogen transport rate is controlled by the bulk diffusion although the pressure dependence of the H-2 flux deviates slightly from Sieverts' law. A sudden increase of the H-2 flux below 50 degrees C is attributed to embrittlement.