Hydrogen Storage Properties, Metallographic Structures and Phase Transitions of Mg-based Alloys Prepared by Super Lamination Technique

We have prepared Mg/Pd laminate composites with (Mg/Pd)=6, 3 and 2.5 atom ratios, by a super lamination technique. The homogeneous Mg-Pd intermetallic compounds, Mg 6 Pd, Mg 3 Pd and Mg 5 Pd 2 , are formed during the initial activation process. We investigated the hydrogen storage properties of these materials. The compounds can reversibly absorb and desorb a large amount of hydrogen, up to 1.46˜0.9 H/M, at 573 K. Except for the Mg 5 Pd 2 -hydrogen system, the pressure composition-isotherms show two plateaux. The mechanism of the phase transition during hydrogenation/dehydrogenation was analyzed by in-situ XRD measurements. These intermetallic compounds absorb and desorb hydrogen through reversible multistage disproportionation and recombination processes.