Diffusion coefficients of hydrogen during absorption and desorption of hydrogen in Pd81Pt19 membrane.: Part I:: Time-lag method

Hydrogen diffusion in Pd81Pt19 membrane was investigated at 288.4 K in hydrogen pressures up to 1000 hPa. Starting with uniformly hydrogen charged membranes, the kinetics of ab- and desorption were followed at symmetrical initial and boundary conditions. The breakthrough times were used for evaluation of the diffusion coefficients. For initial contents of hydrogen above n = H/M = 0.005 (atomic ratio of hydrogen to metal) the diffusion coefficients during desorption are larger than during absorption by about 10%.