Phase transition and hydrogen storage properties of melt-spun Mg_3LaNi_(0.1) alloy

摘要

Nominal Mg_3LaNi_(0.1) alloy was prepared by a single roller melt-spun method. The phase structure and hydrogen storage properties of the obtained ribbons were studied by X-Ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorim-etry (DSC) analysis and pressure-composition isotherm (PCI) measurements. The melt-spun Mg_3LaNi_(0.1) alloy was composed of Mg_3La phase, while fine LaM&Ni grains were precipitated after an aging treatment at room temperature. Both Mg_3La and LaMg_2Ni undertook disproportion reactions upon hydrogenation and decomposed into MgH_2, LaH_3 and Mg_2NiH_4. The melt-spun alloy shows excellent hydrogen absorption kinetics and lowered desorption temperature comparing with the induction-melted alloy, and a maximum hydrogen storage capacity of 3.1 wt.% and a minimum hydrogen desorption temperature of 224 ℃ were achieved. This improvement on the hydrogen storage properties was attributed to the catalytic role of in-situ formed nanocrystalline Mg_2Ni and LaH_2.