The permeability was measured for pressure differentials ranging from 10-3 to 104Pa and for temperatures of between 350 and 1050K (table 65). For each alloy, a square-root dependence of the permeability upon the driving pressure was observed at higher pressures. The pressure at which this relationship no longer applied depended upon the H purity.

Hydrogen Permeation Characteristics of Some Austenitic and Nickel-Base Alloys. E.H.Van Deventer, V.A.Maroni: Journal of Nuclear Materials, 1980, 92[1], 103-11

Figure 10

Diffusivity of H in AISI 347