An investigation was made of the diffusivity of H in high-purity Ba which contained some 73ppmN, 35ppmC, 23ppmFe and 80ppmMn. The H was diffused into semi-infinite bars with their end-surface concentration held constant. The H concentration profiles were then obtained by sectioning the bars and analyzing each section by means of vacuum fusion. It was found that, at temperatures ranging from 200 to 620C, the results were described by:

D (cm2/s) = 4.0 x 10-3 exp[-4.5(kcal/mol)/RT]

Diffusion of Hydrogen in Barium Metal. D.T.Peterson, C.C.Hammerberg: Journal of the Less-Common Metals, 1968, 16[4], 457-60