By using ultra-high vacuum techniques and mass-spectroscopic analyses, an investigation was made of the permeation of H through wrought- and vapor-deposited 3N5-purity tubes at pressures and temperatures ranging from 10-6 to 200torr and from 1050 to 2400K, respectively. At pressures above 1torr, the data obeyed:

P (torr½ l/cm) = 1.5 x 10-3 exp[-31.5(kcal/mol)/RT]

Permeation of Hydrogen through Tungsten and Molybdenum. R.Frauenfelder: Journal of Chemical Physics, 1968, 48[9], 3955-65