Protium diffusion in LaNi5 alloy

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