Hydrogen storage properties of Ti0.95FeZr0.05, TiFe0.95Zr0.05 and TiFeZr0.05 alloys

In this paper, we report the microstructure and hydrogen storage properties of Ti0.95FeZr0.05, TiFe0.95Zr0.05 and TiFeZr0.05 alloys prepared by arc melting. We found that all these alloys are made of a TiFe phase with small amount of zirconium in solid solution and a secondary phase which is zirconium rich. This special microstructure is actually responsible for the enhanced activation (first hydrogenation) kinetics of these alloys. First hydrogenation of Ti0.95FeZr0.05 alloy proceed faster than for the other two alloys. This is probably due to a finer distribution of the bright secondary phase. Pressure-composition isotherms of TiFeZr0.05 and Ti0.95FeZr0.05 alloys are similar while the alloy TiFe0.95Zr0.05 shows the highest capacity. These results demonstrate that a very slight variation of composition could have an important effect of microstructure and hydrogen storage behaviours.