Phase Structure and Electrochemical Properties of La-Mg-Ni System La2Mg0.9Ni7.5Co1.5Al0.1 Hydrogen Storage Alloys Prepared by Melt Spun

Abstract:

The hydrogen storage alloys were prepared using induction melting followed by heating treatment and melt spun. The effect of melt spun on the phase structure, microstructure and electrochemical properties of La2Mg0.9Ni7.5Co1.5Al0.1 was investigated systematically XRD analysis shows that the obvious change of the phase composition of the La2Mgo.gNi7.5Co1.5Al0.1 alloy took place with the increase of quenching rate. The annealed alloy consists of aLa2Ni7 main phase with Ce2Ni7 type structure and a little LaNi3 second phases with PuNi3 type structure. With the increase of quenching rate, the LaNis phase with CaCus type structure and LaMgNi4phase with MgCu4Sn type structure appear in the alloys, the content of the new phases increases but the content of aLa2Ni7 phase and LaNij phase decreases. EPMA analysis indicates that the La2Mg0.9Ni7.5Co1.5Al0.1 alloys prepared by melt spun have fine columnar crystal structure. The electrochemical measurement shows that the quenching rate has little effect on the activation property but the maximum discharge capacity and the high rate discharge ability decrease with the increase of quenching rate. It has a little improvement of the cyclic stability at the lower quenching rate as 5m/s, but the alloy electrode demonstrates better cyclic stability with the further increase of quenching rate as 20 m/s