Influence of the surface processes on the hydrogen permeation through ferritic steel and amorphous Fe40Ni40Mo4B16 alloy specimens

A method for the determination of the gas diffusion coefficient D through thin membranes has been developed taking into account the membrane surface kinetic processes, The hydrogen permeation through STE890 steel and the amorphous alloy Fe40Ni40Mo4B16 has been investigated in a wide temperature range with the aid of a method developed by the authors. It is shown that the theoretical and experimental approach developed for the determination of hydrogen diffusivity and permeation provides the possibility to gain reasonable results and can be successfully used for further studies. A criterion was set out to determine when the surface kinetic processes should be taken into account. The permeation and diffusion coefficients obtained with the aid of the present method, show a good correlation with those obtained by other authors with other methods. (C) 1997 Elsevier Science B.V.