Preparation and hydrogen-storage properties of 90(Mg-23.5Ni)-10Ta2O5 alloy by melt spinning and oxide addition

The 90 wt.% (Mg-23.5 wt.% Ni)-10 wt.% Ta2O5 alloy (designated as (Mg-23.5Ni)-10Ta2O5) was prepared by pulverizing the melt spun and heat treated Mg-23.5 wt.% Ni alloy with the Ta2O5 prepared by spray-conversion in a planetary ball mill. The activated (Mg-23.5Ni)-10Ta2O5 alloy had a higher hydriding rate than the activated Mg-23.5Ni alloy but a similar dehydriding rate. The activated (Mg-23.5Ni)-10Ta2O5 alloy absorbed 4.64 wt.% H for 5 min (i.e., a hydriding rate of 0.93 wt.% H/min) at 573 K, and desorbed 5.02 wt.% H for 5 min (i.e., a dehydriding rate of 1.00 wt.% H/min) at 623 K. The activated (Mg-23.5Ni)-10Ta2O5 alloy exhibited a hydrogen-storage capacity of 6.68 wt.% H.