Protium diffusion in LaNi₅ alloy

Diffusion of protium in the α phase (solid solution), the ά phase (α phase dehydrided from the β phase) and the β phase (hydride) of LaNi₅-H alloys was studied by the desorption method. It was observed that the diffusion coefficient of protium in the β phase was a little higher than that in the α phase and that these were much higher than that in the ά phase. The difference between the diffusion coefficients in the three phases is attributed to the difference in the protium concentration between the α phase and the β phase and to the difference in the trapping density between the α phase and the ά phase.