Hydriding and dehydriding characteristics of nanocrystalline and amorphous Mg20–xLaxNi10(x=0–6) alloys prepared by melt-spinning

• Published in: Journal of rare earths Vol. 27; no. 3; pp. 514 - 519
• Main Authors: ZHANG, Yanghuan, ZHAO, Dongliang, REN, Huiping, GUO, Shihai, WANG, Qingchun, WANG, Xinlin
• Format: Journal Article
• Language: English
• Published: 01.06.2009
• Subjects: melt-spinning; Mg2Ni-type hydrogen storage alloy; hydriding and dehydriding characteristics; structure; rare earths
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/S1002-0721(08)60280-X

O6; In order to improve the hydrogenation and dehydrogenation performances of the Mg2Ni-type alloys, Mg was partially substituted by La in the alloy, and melt spinning technology was used for the preparation of the Mg20-xLaxNi10 (x=0, 2, 4, 6) hydrogen storage alloys. The structures of the alloys were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). It was found that no amorphous phase formed in the as-spun La-free alloy, but the as-spun alloys containing La held a major amorphous phase. When La content x≤2, the major phase in the as-cast alloys was Mg2Ni phase, but with further increase of La content, the major phase of the as-cast alloys changed into LaNi5+LaMg3 phase. Thermal stability of the as-spun alloys was studied by differential scanning calorimetry (DSC), showing that spinning rate was a negligible factor on the crystallization temperature of the amor-phous phase. The hydrogen absorption and desorption kinetics of the as-cast and as-spun alloys were measured using an automatically con-trolled Sieverts apparatus, confirming that the hydrogen absorption and desorption capacities and kinetics of the as-cast alloys clearly in-creased with rising La content. For La content x=2, the as-spun alloy displayed optimal hydrogen desorption kinetics at 200 ℃.