Gas-driven permeation of H through metal membranes in the surface-limited regime was analyzed. An analytical solution for the concentration and permeation flux as a function of time was given for permeation through the asymmetric membrane having different conditions on the inlet and outlet sides. The features of the steady-state and transient permeation were discussed. Comparison of calculations with an experiment on D permeation through V, which was available from literature, was performed. It was demonstrated that the parameters, extracted from the measurements of the permeation rate in surface-limited regime were very uncertain. Even the calculations with opposite asymmetries could be equally well adjusted to the experiment. Non-zero initial conditions in surface-limited regime experiments were additional source of uncertainty

Measurements of the accumulation in a closed volume instead of the permeation rate could seriously mislead in the interpretation of the experiment. Complementary experiments on permeation in two opposite directions and measurements of permeation decay could increase the reliability of the data obtained.

Gas-Driven Hydrogen Permeation in the Surface-Limited Regime. A.Pisarev, V.Shestakov, R.Hayakawa, Y.Hatano, K.Watanabe: Journal of Nuclear Materials, 2003, 320[3], 214-22

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