A simulation program was developed to analyze H entrapment during H permeation experiments where the input side H concentration was constant and the exit side H concentration was zero. The simulations performed focused on the effect of traps on the exit side H flux and that on the capture and release of H by traps as a function of the distance from the entry surface. The number of dimensionless parameters to be defined in the presence of traps was much higher than in the absence of traps. It was found that in several cases the first breakthrough time of H was a linear function of the trap

concentration. However, when the capture of H by traps was slow, the permeation curve may have a very unusual shape, and the trap saturation profile changed substantially during the permeation experiment. The impact of the H entrapment kinetics on the result of permeation experiments in connection with the industrial test of enamel-grade steel plates was also discussed.

Theoretical Analysis of Entrapment Kinetics in Hydrogen Permeation Experiments. L.Péter, B.Almási, B.Veró, H.Schneider: Materials Science and Engineering A, 2003, 339[1-2], 245-54