Effect of preparation routes on the performance of a multi-component AB₂-type hydrogen storage alloy

Abstract

This article presents experimental results on the preparation and characterisation of a multi-component AB2–type intermetallic hydrogen storage alloy (A = Ti0.85Zr0.15, B = Mn1.22Ni0.22Cr0.2V0.3Fe0.06). The alloy samples were prepared by induction melting using Y2O3-lined alumo-silica and graphite crucibles. The characterisation results were compared with the ones for the reference sample of the same composition prepared by arc melting. It has been shown that the induction-melted samples exhibit reduced hydrogen sorption capacities and sloping plateaux on the pressure composition isotherms (PCI’s). The origin of the observed effects has been shown to be in the inhomogeneity of the induction-melted alloys and their contamination due to crucible—melt interaction, particularly pronounced for the alloy melted in the alumo-silica crucible; this alloy was additionally characterised by the decrease of Zr/Ti ratio and, in turn, higher plateau pressures of the PCI’s.