Mechanically alloyed MmNi(5)-type materials for metal hydride electrodes

Nanocrystalline MmNi(5)-type alloys have been prepared by mechanical alloyi ng (MA) followed by annealing. The structural and electrochemical propertie s of these materials have been investigated at room temperature. The amorph ous phase forms directly from the starting mixture of the elements, without other phase formation. Heating the MA powders at 1070 K for 1 h resulted i n the formation of the hexagonal CaCu5-type structure. For nanocrystalline MmNi(4.2)Al(0.8) material discharge capacities of 207 mAh g(-1) were obtain ed. (C) 1999 Elsevier Science S.A. All rights reserved.