Hydrogen sorption properties of Mg-1 wt.% Ni-0.2 wt.% Pd prepared by reactive milling

Despite the large differences in melting points and the high vapour pressure of Mg, we succeeded in the preparation of induction-melted Mg-1 wt.% Ni-0.2 wt.% Pd alloy. The alloy was then reactively ball milled in 10 bar hydrogen. The structural changes during milling were characterised by XRD and high resolution scanning electron microscopy. The hydrogen sorption properties have been systematically studied by gravimetric analysis in a wide temperature and pressure range for absorption (1-10 bar, 50-300 ° C) and desorption (250-350 ° C, 50 mbar-1 bar). The combined effects of Pd and Ni additions prove particularly useful in providing superior kinetics at very modest absorption conditions and excellent cyclic stability. These data are compared with those of nanocrystalline MgH2 powders, obtained by intensive milling in argon atmosphere.