Development of Mg-xFe₂O₃-yNi Hydrogen-Storage Alloys by Reactive Mechanical Grinding

Mg-x wt% Fe₂O₃-y wt% Ni samples were prepared by reactive mechanical grinding in a planetary ball mill, and their hydrogen-storage properties were investigated and compared. Activations of Mg-5Fe₂O₃- 5Ni was completed after one hydriding (under 12 bar H2) – dehydriding (in vacuum) cycle at 593 K. At n = 2, Mg-5Fe₂O₃-5Ni absorbed 3.43 wt% H for 5 min, 3.57 wt% H for 10 min, 3.76 wt% H for 20 min, and 3.98 wt% H for 60 min. Activated Mg-10Fe₂O₃ had the highest hydriding rate, absorbing 2.99 wt% H for 2.5 min, 4.86 wt% H for 10 min, and 5.54 wt% H for 60 min at 593 K under 12 bar H2. Activated Mg-10Fe₂O₃-5Ni had the highest dehydriding rate, desorbing 1.31 wt% H for 10 min, 2.91 wt% H for 30 min, and 3.83 wt% H for 60 min at 593 K under 1.0 bar H2