Mischmetal- and Zr-based alloys, of AB5 or AB2 type, were characterized by using powder X-ray diffractograms. The H absorption kinetics were studied at 450 to 650C and 10 to 100mbar, with a maximum H to host alloy formula unit ratio of 0.01, by using a pressure reduction technique. The diffusion coefficient of the H interstitials was deduced from the H absorption kinetics experiments. The data for ZrMnFe0.5Ni0.5 could be described by:

D (cm2/s) = 6.5 x 10-3 exp[-0.295(eV)/kT]

The diffusion coefficient for mischmetal-based alloys was about an order of magnitude higher than that for Zr-based alloys.

N.Mani, N.Ravi, S.Ramaprabhu: Journal of Physics - Condensed Matter, 2005, 17[34], 5201-6