It was recalled that the diffusivities of H isotopes in Pd alloys had been deduced from the rate of electrical resistivity increase during H (D) ordering at around 50K. The interstitially dissolved H isotopes interacted with the alloying atoms, whose size was different to that of the Pd atoms, because of the volume dilatation which was caused by the introduced H isotopes. Here, the diffusivities and migration energies of H isotopes in Pd-Ni alloys were determined by measuring the electrical resistivity increase that was due to the ordering of H isotopes at around 50K. The results were then compared with those for pure Pd, Pd-Fe and Pd-Ag alloys. It was found that the various published results contradicted each other. These discrepancies were attributed to differences in the experimental conditions, such as the H concentration and the temperature range.

K.Yamakawa, H.Maeta: Scripta Metallurgica et Materialia, 1994, 31[7], 803-8