Compositional and structural characteristics of MgNi alloy prepared by mechanical alloying for use as negative electrodes in nickel-metal hydride batteries

From the elemental analysis by EPMA, it was found that the bulk of MgNi alloy particles prepared by mechanical alloying (MA) were uniform composition with Mg/Ni=1 and a nickel-rich surface, while in the bulk of the alloy particles prepared by induction melting (IM) the Mg/Ni ratio was not uniform. Moreover, it was confirmed by transmission electron microscopy (TEM) and electron diffractometry that the MgNi alloys prepared by MA and IM had amorphous and crystalline structures, respectively. This was believed to be responsible for the difference of the discharge capacities between two kinds of MgNi alloys. (C) 1997 Elsevier Science S.A.