Structures and electrochemical performances of RE-Mg-Ni-Mn-based alloys prepared by casting and melt spinning

La-Mg-Ni-Mn-based AB2-type La1–xCexMgNi3.5Mn0.5(x=0–0.4) alloys were prepared by melt spinning technology. The detections of X-ray diffraction(XRD) and scanning electron microscopy(SEM) indicated that the experimental alloys consisted of a major phase LaMgNi4and a secondary phase LaNi5. With spinning rate growing, the abundance of LaMgNi4phase increased and that of LaNi5phase decreased. Moreover, with the melt spinning rate increasing, both the lattice constants and cell volumes increased, and further accelerated the grains refinement of the alloys. The electrochemical tests showed that the as-spun alloys possessed excellent capability of activation, achieving the maximum discharge capacities just at the first cycling without any activation needed. As for the as-spun alloys, its discharge potential characteristics could be improved obviously by adopting the technology of melt spinning. In addition, the melt spinning raised electrochemical cycle stability of the alloys, the main reason was that the melt spinning enhanced the anti-pulverization ability of the alloys. With spinning rate increasing, the discharge capacity of the alloys presented a tendency to increase firstly then decrease. Moreover, the electrochemical kinetics of the alloys showed the same trend under fixed condition.