The permeation characteristics were investigated in pure Mg membranes, with a Pd over-layer, by using a gas permeation technique at 473 to 493K, at H pressures ranging from 0.1 to 10kPa. In the case of thicker (above 2mm) specimens, the permeation rate was controlled by H diffusion in the bulk. The diffusion data could be described by:

D (m2/s) = 1.54 x 10-6 exp[-24100/RT]

The steady-state H permeability was described by:

D (mol/ms√Pa) = 2.77 x 10-7 exp[-35700/RT]

The diffusivity and permeability were independent of the applied H pressure; thus suggesting that D was independent of the H content and that the H solubility obeyed Sieverts’ law. The H solution constant was determined to be equal to 0.18exp[-11600/RT]/m3√Pa.

C.Nishimura, M.Komaki, M.Amano: Journal of Alloys and Compounds, 1999, 293-295, 329-33