Hydrogen storage properties of Mg76Ti12Fe12-xNixMg76Ti12Fe12-xNix(x=0,4,8,12)(x=0,4,8,12) alloys by mechanical alloying

Mg76Ti12Fe12-xNixMg76Ti12Fe12-xNix(x=0,4,8,12)(x=0,4,8,12) alloys were prepared by mechanical alloying and the hydrogen storage properties were investigated systematically. In Mg76Ti12Fe12Mg76Ti12Fe12 and Mg76Ti12Ni12Ti12Mg76Ti12Ni12Ti12 alloys, the main binary alloy phase is Fe2TiFe2Ti and Mg2NiMg2Ni, respectively. There are same binary alloy phase structures included Fe2TiFe2Ti, Mg2NiMg2Ni and NiTi in Mg76Ti12Fe8Ni4Mg76Ti12Fe8Ni4 and Mg76Ti12Fe4Ni8Mg76Ti12Fe4Ni8 alloys. For Mg76Ti12Fe12-xNixMg76Ti12Fe12-xNix(x=0,4,8,12)(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. Mg76Ti12Fe8Ni4Mg76Ti12Fe8Ni4 shows the highest hydrogen absorption and desorption rate among Mg76Ti12Fe12-xNixMg76Ti12Fe12-xNix(x=0,4,8,12)(x=0,4,8,12) alloys. Fe and Ni coexistence is favorable to improve hydrogen storage properties. For Mg76Ti12Fe8Ni4Mg76Ti12Fe8Ni4 alloy, the amorphous degree increase with the milling time, and the amorphous degree increase is unfavorable to improve hydrogen storage capacity.