Influence of the Preparation Routes on Chemical and Phase Composition and Hydrogen Sorption Performances of Hydrogen Storage Alloys based on TiFe Intermetallic

A promising way to solve the problems of hydrogen storage for energy systems is in the use of metal hydrides, especially, the ones on the basis of titanium—iron alloys characterized by low cost and easily available feedstock. However, hydrogen storage performances of TiFe-based intermetallic alloys are very sensitive to a number of factors including contamination of the final product with non-metallic impurities, first of all, oxygen. This work aimed at finding the ways to mitigate these undesired effects presents results of the experimental studies of chemical and phase composition, along with hydrogen sorption properties of the alloys Ti_1 + xFe_1 – yM_y (x = –0.07…+0.19, y = 0–0.2, M = Mn, V) prepared using small-to-medium scale arc- and induction melting facilities from industrial-grade quality raw materials. The most effective way to decrease the oxygen contamination and improve the hydrogen sorption performance was found to be addition of minor amounts of a mischmetal deoxidizer to the starting charge followed by induction melting. Additional factors influencing on the properties of the studied alloys and discussed in this work are the details of the melting procedure and the base composition of the charge including Ti : Fe atomic ratio, type of the metal additive (M) substituting iron in the alloy, as well as possibility of formation of minor amount of the oxygen-containing intermetallic Ti₄(Fe,M)₂O_1 – x (η-phase) known as efficient hydrogenation catalyst.