Role of microstructure in the hydrogen storage capacity and kinetics of TiFe AB-type alloys

This investigation evaluates how the microstructure of TiFe AB-type alloys, produced by vacuum induction melting and different cooling rates, affects their solid-state hydrogen storage capacity and kinetics. The chemical and phase composition was evaluated by X-ray energy dispersive spectroscopy and X-ray diffraction. While the microstructure of the alloys was observed by scanning electron microscopy. Once the samples were obtained, a mechanical milling process was carried out for 1 h to reduce the particle size and eliminate possible surface oxide layers. Subsequently, the kinetics and hydrogen storage capacity were evaluated using a self-constructed Sieverts-type apparatus. The results obtained show that a mixture of TiFe and TiFe 2 crystalline phases was obtained in the molten samples. The highest hydrogen storage capacity obtained was ∼1.7 wt%, showing a decrease as the proportion of secondary phases, such as TiFe 2 and Fe-rich phases, increased.