Precise measurements of H permeation through high-purity samples were performed by using the gaseous permeation technique and H pressures of 0.001 to 0.1MPa, at 420 to 1100K. It was found that the diffusivity could be described by:

D (cm2/s) = 6.04 x 10-4 exp[-1.66(kcal/mol)/RT]

T.Tanabe, Y.Yamanishi, S.Imoto: Transactions of the Japan Institute of Metals, 1984, 25[1], 1-10