Large-grained (4mm) specimens of 4N5-purity material were charged with high-purity H by heating at 600C for 48h. The diffusion coefficients were deduced from desorption measurements. The diffusivity at 450 to 625C could be described by:

D (cm2/s) = 1.01 x 10-1 exp[-11.4(kcal/mol)/RT]

R.A.Outlaw, D.T.Peterson, F.A.Schmidt: Scripta Metallurgica, 1982, 16[3], 287-92