Hydrogenation improvement of TiFe by adding ZrMn2

Abstract

In this paper, we report the microstructure and hydrogen storage properties of TiFe + x wt.%ZrMn2 (x = 2, 4, 8, 12) alloys prepared by arc melting. Each alloy was made of two phases: a TiFe phase with very small amount of zirconium and manganese, and a second phase which has a higher proportion of zirconium and manganese. We found that the first hydrogenation kinetics increase with x. This is most likely due to the presence of zirconium-rich secondary phase that acts as a gateway for hydrogen to enter the main TiFe phase. Pressure-composition isotherms also show that increasing x decreases the absorption plateau pressure. Moreover, for x = 12, air exposure had a minimal impact on hydrogen absorption behaviour. Finally, we found that cold rolling has minimal effect on the activation kinetics of TiFe + x wt.%ZrMn2 (x = 4) alloy.