Microstructure and hydrogen storage properties of Zr0.8Ti0.2Co1-xFex (x=0, 0.1, 0.2, 0.3) alloys

In the present study, Zr0.8Ti0.2Co1-xFex (x = 0, 0.1, 0.2 and 0.3) alloys were prepared by arc melting method. The effect of Fe substitution on microstructure and hydrogen storage properties was studied systematically. The phase structure and hydrogen storage properties were characterized by X-ray diffraction (XRD), Electron Probe Micro-analysis (EMPA) and Sievert's type volumetric apparatus. XRD and EPMA analysis show that Zr0.8Ti0.2Co alloy forms cubic phase ZrCo and traces of ZrCo2, while the alloys of composition with x = 0.1, 0.2 and 0.3 form cubic phase ZrCo with the secondary Laves phases Zr(Co,Fe)2 and Zr2Co. The cell volumes and content of the secondary phase increase gradually as the content of Fe substitution increases. The hydrogen storage experiment shows that Fe substitution for Co ameliorates initial hydriding kinetic property and shortens the incubation duration of the Zr0.8Ti0.2Co1-xFex (x = 0.1, 0.2 and 0.3) alloys, compared with Zr0.8Ti0.2Co alloy. The improved kinetic property is due to the catalyst effect of the secondary phase, which makes it favorable for the application in International Thermonuclear Experimental Reactor (ITER). (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.