By using mass-spectroscopic analyses, a study was made of the permeation of H through Mo membranes at 400 to 1200C, under pressures of 1 to 200torr. The permeation data could be described by:

P (cm2/s atm½) = 2.6 x 10-2 exp[-19.3(kcal/mol)/RT]

while the diffusion data obeyed:

D (cm2/s) = 2.0 exp[-17.8(kcal/mol)/RT]

The results indicated that the penetration of H into Mo did not occur via a purely diffusive mechanism, and that surface effects played an appreciable part in the process.

A.P.Zakharov, V.M.Sharapov: Fiziko-Khimicheskaya Mekhanika Materialov, 1971, 7[6], 54-8