Hydrogen permeation was investigated, in pure magnesium membranes with a palladium overlayer, using a gas permeation technique at 473 to 493K and 0.1 to 10kPa of H. In thicker specimens (>2mm), the permeation process was rate-controlled by the diffusion of hydrogen in the bulk. The diffusion was found to be described by:

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

The steady-state hydrogen permeability was given by:

Φss(molH2/msPa1/2) = 2.77 x 10-7exp[-35700/RT]

Both were independent of the applied hydrogen pressure; suggesting that D was independent of the hydrogen content, and that the H solubility obeyed Sieverts' law. The hydrogen solution constant was described by:

K(molH2/m3Pa1/2) = 1.8 x 10-1exp[-11600/RT]

Hydrogen Permeation through Magnesium. C.Nishimura, M.Komaki, M.Amano: Journal of Alloys and Compounds, 1999, 293, 329-33