The diffusion of H interstitials was studied in Ti0.1Zr0.9Mn0.9V0.1Fe0.5Ni0.5, (Ti0.1Zr0.9)1.1Mn0.9V0.1Fe0.5Ni0.5 and Ti0.1Zr0.9Mn0.9V0.1Fe0.5Co0.5 alloys having the C14 structure, at 400 to 600C under H gas pressures of up to 100mbar and H concentrations of up to 0.012H atoms per metal formula unit. It was noted that the H absorption was exothermic and that the partial enthalpies of solution per H atom were −0.210 and −0.248eV for Ti0.1Zr0.9Mn0.9V0.1Fe0.5Ni0.5 and (Ti0.1Zr0.9)1.1Mn0.9V0.1Fe0.5Ni0.5. The diffusion coefficient of the H interstitials was determined from the kinetics of H-gas absorption. At 500C, the diffusion coefficients (figure 10) were about 5 x 10-5cm2/s; with activation energies of 0.292 to 0.423eV.

Solubility and Diffusion of Hydrogen in AB2-Type Laves Phase Alloys. M.Kandavel, S.Ramaprabhu, M.Jung, H.Wipf: Journal of Alloys and Compounds, 2005, 404-406, 265-8

Figure 10

Diffusion of H in (Ti,Zr)(Mn,V)(Fe,Co), (Ti,Zr)(Mn,V)(Fe,Ni) Alloys

(Squares: Ti0.1Zr0.9Mn0.9V0.1Fe0.5Ni0.5, circles: (Ti0.1Zr0.9)1.1Mn0.9V0.1Fe0.5Ni0.5,

triangles: Ti0.1Zr0.9Mn0.9V0.1Fe0.5Co0.5