International Journal of Hydrogen Energy, Vol.44, No.55, 29116-29122, 2019
Exploration of Ti substitution in AB(2)-type Y-Zr-Fe based hydrogen storage alloys
To improve the hydrogen storage properties of Y-Zr-Fe alloys, the alloying with Ti was carried out to obtain Y0.7Zr(0.3-x)TixFe2 (x = 0.03, 0.09, 0.1, 0.2) alloys by different processes. It was expected that Ti would substitute Zr and decrease the lattice constant of YFe2-based C15 Laves phase. All Y-Zr-Ti-Fe quaternary alloys consist of the main Y(Zr)Fe-2 phase and the minor YFe3 phase. Despite the large solubility of Ti in Zr or Zr in Y, the Ti incorporation into Y-Zr-Fe alloys results in the inhomogeneity of Y and the segregation of Ti, and thus decreases the hydrogen storage capacity. Only the alloy Y0.7Zr0.27Ti0.03Fe2 containing very few Ti shows the substitution of Ti to Zr and the resultant improvement in the dehydriding equilibrium pressure. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.