The permeation of H through a slab sample containing isolated H traps was analyzed. The analysis was based upon a flux continuity model that considers both the absorption and desorption processes. An analytical solution in series was derived for a dilute system with a low trap coverage fraction. According to this solution, it was possible to characterize isolated H traps using only H permeation tests on 2 groups of samples with each group having different thicknesses. One group of samples, serving as a reference, was made of a pure matrix material without any H traps, while the other group of samples was made of the same matrix material with traps. The proposed multi-sample method was demonstrated by numerical calculations and plots, from which the H diffusion coefficient, the desorption rate, the absorption parameter, the trap density and the trap enthalpy could be determined using permeation data on the steady flux and the time lag. The maximum error caused by the numerical calculations was less than 7%.

Characterization of Isolated Hydrogen Traps by Hydrogen Permeation Experiments. T.Y.Zhang, I.Wat: Journal of Applied Physics, 2003, 93[10], 6016-24