Microstructure and Electrochemical Properties of Co-free Over-stoichiometric Alloys Ml(NiMnAlFe)_(5.4)

Abstract:

The Co free over stoichiometric alloy Ml (NiMnAlFe) 5.4 were prepared using conventional cast, rapid solidification (melt spinning) and annealing processes. The microstructure and electrochemical properties of these alloys were investigated comparatively. XRD analyses show that three kinds of the alloys are all composed of main phase with CaCu 5 structure and the second phase (AlNi 3), but the amount of the second phase in the melt spinning alloy is less, and the second phase in annealed alloy disappeared. The electrochemical analyses show that the melt spun and annealed alloys all have better cycling stability than that of conventional cast alloy, but their discharge capacity and high rate dischargeability are little lower than that of conventional cast alloy.