Hydrogen sorption characteristics of a Mg2Ni, V and Ti containing nanocomposite prepared by mechanical alloying

The hydrogen absorption-desorption characteristics of a 70% Mg, 15% Mg 2 Ni, 10%V and 5% Ti containing composite material, obtained by mechanical alloying in a planetary mill under argon, were studied. The experimental data on the kinetics of hydriding and dehydriding and on the absorption capacity values, established at various temperatures and hydrogen pressures were compared with those of a previously studied composite, prepared by the same method but containing no titanium. The simultaneous presence of two hydride-forming 3d-metals along with Mg 2 Ni in the composite was shown to lead to improved hydriding kinetics, high hydrogen absorption capacity values, observed at temperatures lower than 573 K and pressures below 1 MPa. The catalytic effect of the additives was attributed to the formation, together with Mg 2 NiH 4 , of two nonstoichiometric hydrides, VH 0.8 and TiH 1.92 , thus facilitating nucleation and resulting in an interface area increase.