Study of Mg6Pd alloy synthesized by cold rolling

In this paper we report the hydrogen storage properties of Mg6Pd alloy synthesized by cold rolling and ball milling followed by heat treatment. The heat treatment was performed at 623K, a much lower temperature than the peritectic temperature of Mg6Pd (973K). After heat treatment the reaction is complete. The laminated sample is much easier to activate under hydrogen and has a better resistance to air exposure than the ball-milled sample. The hydrogenation is a reversible dispropornation reaction with generation of magnesium hydride and Mg5Pd2 alloy. The hydrogenation pressure-composition curve shows the presence of two plateaus: the first plateau corresponds to the decomposition of Mg6Pd into Mg78.5Pd21.5 and MgH2 while the second plateau is the decomposition of Mg78.5Pd21.5 into Mg5Pd2 and MgH2. As the only hydride phase is MgH2, the dehydrogenation curves show only the plateau corresponding to magnesium hydride. Cold rolling is proved to be an efficient and easy way to synthesize Mg-Pd intermetallics.