Hydrogen gas driven permeation through fine-grain graphite MPG-8 was investigated in the range of thickness from 0.55 to 4.38mm and pressures ranging from 10−2 to 1Pa. The permeation rate was proportional to the gas pressure and inversely proportional to the thickness. It was concluded that gas driven permeation through fine-grain graphite was due to gas flow through the internal porosity network in the molecular regime. The specific bulk conductivity of the graphite was between 5 x 1015 and 7.3 x 1015molecules/smPa. Surface treatment influences the permeation through membranes thinner than 1mm. Surface polishing, washing in the ultrasonic bath, H and Ar plasma irradiation, methane plasma treatment, Ar ion irradiation, and annealing at 1000K had a zero to 10% influence upon the permeation rate.

Permeation of Hydrogen through MPG-8 Graphite. A.Spitsyn, A.Pisarev, A.Skovoroda, V.Gureev, Y.Martynenko: Journal of Nuclear Materials, 2007, 363-365, 833-8