Hydrogen storage properties of alloys by mechanical alloying

Mg 76 Ti 12 Fe 12 - x Ni x ( x = 0 , 4 , 8 , 12 ) alloys were prepared by mechanical alloying and the hydrogen storage properties were investigated systematically. In Mg 76 Ti 12 Fe 12 and Mg 76 Ti 12 Ni 12 Ti 12 alloys, the main binary alloy phase is Fe 2 Ti and Mg 2 Ni , respectively. There are same binary alloy phase structures included Fe 2 Ti , Mg 2 Ni and NiTi in Mg 76 Ti 12 Fe 8 Ni 4 and Mg 76 Ti 12 Fe 4 Ni 8 alloys. For Mg 76 Ti 12 Fe 12 - x Ni x ( x = 0 , 4 , 8 , 12 ) alloys, the hydrogen storage capacity is 2.88, 3.31, 3.12 and 2.24 wt%, respectively. The hysteresis between hydrogen absorption and desorption decreases gradually with increasing the amount of substitution Ni for Fe. Mg 76 Ti 12 Fe 8 Ni 4 shows the highest hydrogen absorption and desorption rate among Mg 76 Ti 12 Fe 12 - x Ni x ( x = 0 , 4 , 8 , 12 ) alloys. Fe and Ni coexistence is favorable to improve hydrogen storage properties. For Mg 76 Ti 12 Fe 8 Ni 4 alloy, the amorphous degree increase with the milling time, and the amorphous degree increase is unfavorable to improve hydrogen storage capacity.