Hydrogen Storage Characteristics of Melt Spun Mg-23.5Ni-xCu Alloys and Mg-23.5Ni-2.5Cu Alloy Mixed with Nb2O5 and NbF5

Mg-23.5 wt%Ni-xwt%Cu (x=2.5, 5 and 7.5) samples for hydrogen storage were prepared by melt spinning and crystallization heat treatment from a Mg-23.5 wt%Ni-5 wt%Cu alloy synthesized by the gravity casting method. They were then ground under H2 to obtain a fine powder. Among these samples the Mg- 23.5Ni-2.5Cu sample had the highest hydriding and dehydriding rates after activation. The Mg-23.5Ni-2.5Cu sample absorbed 3.59 and 4.01 wt%H for 10 and 60 min, respectively, at 573K under 12 bar H2. The activated 88(87.5Mg-10Ni-2.5Cu)-5Nb2O5-7NbF5 sample absorbed 2.93 wt%H for 10 min, and 3.14 wt%H for 60 min at 573K under 12 bar H2.