Preparation by gravity casting and hydrogen-storage properties of Mg–23.5 wt.%Ni–(5, 10 and 15 wt.%)La

Mg–23.5 wt.%Ni–(5, 10 and 15 wt.%)La alloys were prepared by gravity casting and their hydrogen-storage properties were examined after pulverizing. The gravity cast Mg–23.5Ni–(5, 10 and 15)La alloys consist of α-Mg, Mg 2Ni and Mg 17La 2 phases. The activated Mg–23.5Ni–10La alloy has the highest hydrogen-storage capacity of 4.96 wt.%H (from P– C– T curve) and the highest initial hydriding rate (hydrogen content 3.83 wt.%H at 10 min) with an initial hydrogen pressure in the channel of 11 bar H 2 at 573 K. This is attributed to its containing the largest amount of the Mg 17La 2 phase, which is easily dissociable during the hydriding reaction.