Hydrogen diffusion in LaNi5-H, LaNi5−xAlx-H (x = 0.05, 0.12, 0.25, 0.5, 1) and LaNi5−yCoy-H (y = 0.25, 2) alloys was studied by the desorption method with the help of measurements of the thermal desorption spectrum. The diffusion of H in LaNi5-H alloy was delayed owing to the trapping by lattice defects induced by hydrogenation and it could be concluded that trapping sites were mainly vacancies and vacancies clusters. For LaNi5−xAlx-H alloys, the temperature dependence of the H diffusivities in the range of x = 0.12–1 was much different from those at x = 0 and 0.05. On the other hand, the substitution of Co for a part of Ni in LaNi5 enhances the H diffusivity. These variations of the H diffusivities by the substitution of Al or Co depend on the number of sites occupied by hydrogen, the densities of trapping sites and the binding energy between a H atom and a trapping site.

Hydrogen Diffusion by Substitution of Aluminum and Cobalt for a Part of Nickel in LaNi5-H Alloy. K.Asano, Y.Hashimoto, T.Iida, M.Kondo, Y.Iijima: Journal of Alloys and Compounds, 2005, 395[1-2], 201-8

Table 8

Diffusivity of Ni in Ni-Fe-Al Alloys

continued

Table 8 (continued)

Diffusivity of Ni in Ni-Fe-Al Alloys