Investigation On Crystallization And Electrochemical Properties Of The Mg-Ni-La Bulk Metallic Glasses

Mg based amorphous alloys have excellent hydrogen absorption kinetics and hydrogen storage properties of absorbing, it is also widely concerned by Ni/MH researchers. This paper introduces the research progress at home and abroad of the hydrogen storage properties of Mg-Ni based amorphous alloy, then prepared the Mg-Ni-La bulk amorphous alloy by using the self-developed mold injection equipment.The microstructure of Mg-Ni-La amorphous alloy were tested and analyzed by XRD、SEM、DSC and other instruments, the electrochemical properties of Land test and P-C-T test system on Mg-Ni-La amorphous alloy were studied in detail.Studied on the effects of adding rare earth element Y amorphous forming ability and electrochemical hydrogen storage properties of Mg-Ni-La amorphous alloys.This is the ball milling method to refine alloy particles, and studied the influence of ball milling time on the electrochemical properties of Mg-Ni-La amorphous alloy electrode. When the discharge capacity after ball milling6h amorphous alloy can reach395.7mAh/g, and after charge discharge cycling 20times its discharge capacity retention rate can reach90.25%, is the best among the tested data comprehensive performance. After ball milling amorphous alloy particles has been significantly refined, and with the increase in milling time of amorphous alloy particle more fine, and amorphous alloy particle angularity also gradually be polished, its shape becomes uniform, also has become the trend of globular material.P-C-T curve of the amorphous alloy hydrogen storage material was determined by Electrochemical methods, and electrochemical hydrogen storage properties of Mg6oNi23.6La16.4amorphous alloy electrode were also studied, the results show that the Mg6oNi23.6La16.4amorphous alloy electrode charging voltage between-0.9to-1.1V, at the same time, with the charge capacity increasing, the charging voltage also on the rise. The discharge voltage is between-0.86～1.0V, and from0to300mAh/g there is a more obvious discharge platform.Electrode in298K under the0.01MPa platform between hydrogen and0.1MPa, the maximum discharge capacity can reach1.5938%.Through the research discovery, by adding the elements of Y, Mg-Ni-La alloy have the lower corresponding phase region Δ Tx, by contrast, supercooled liquid Mg60Ni23.6La15.9Y0.5alloy corresponding phase region Δ Tx is the biggest, the heating rate increased from10K/min to80K/min,5characteristic temperature of amorphous Mg60Ni23.6La15.9Y0.5alloy also moved to high temperature region, at the same time, the supercooled liquid region Δ Tx increase gradually.Then the experimental study on the electrochemical properties of Mg60Ni23.6La15.9Y0.5amorphous alloy electrode was operated, the results showed that Mg6oNi23.6La15.9Y0.5amorphous alloy electrode during charge and discharge in the amorphous crystallization mechanism was in slow, at the same time in the circulation process to produce Mg2NiH4and Mg2Ni crystal phase, and with the charge discharge cycles on the surface of alloy electrode there is to be formed by oxidation corrosion liquid electrode Mg(OH)2. Addition of rare earth element Y of the amorphous alloy electrode discharge capacity and capacity retention rate were increased at first and then decreases, and the high rate discharge performance is increased.Crystallization of Mg6oNi23.6La15.9Y0.5amorphous alloy electrode amorphous structure is an important reason why the recession in its discharge capacity of electrode, while the non cause oxidation corrosion amorphous alloy electrode in the electrolyte and its discharge capacity.