Nanocrystalline Hydrogen Storage Alloys Formed by Mechanical Alloying

Abstract

The structural and electrochemical properties of a range of alloys, including: ZrV 2 , ZrV 1.5 Ni 0.5 , which have the cubic MgCu 2 structure, Zr 0.35 Ti 0.65 V 0.85 Cr 0.26 Ni 1.30 , which has the hexagonal MgZn 2 structure and MmNi 5 , MmNi 4.2 Al 0.8 , MmNi 3.5 Co 0.7 Al 0.8 , which have the hexagonal CaCu 5 type structure, have been investigated. These alloys have been prepared using mechanical alloying (MA) followed by annealing. The amorphous phase forms directly from the starting mixture of the elements, without other phase formation. Heating the MA samples at 1070 K for 1 h resulted in the creation of ordered alloys. For some nanocrystalline materials discharge capacities of 210 mAh g -1 were obtained.