Study of the Microstructural and First Hydrogenation Properties of TiFe Alloy with Zr, Mn and V as Additives

In this paper, we report the effect of adding Zr + V or Zr + V + Mn to TiFe alloy on microstructure and hydrogen storage properties. The addition of only V was not enough to produce a minimum amount of secondary phase and, therefore, the first hydrogenation at room temperature under a hydrogen pressure of 20 bars was impossible. When 2 wt.% Zr + 2 wt.% V or 2 wt.% Zr + 2 wt.% V + 2 wt.% Mn is added to TiFe, the alloy shows a finely distributed Ti2Fe-like secondary phase. These alloys presented a fast first hydrogenation and a high capacity. The rate-limiting step was found to be 3D growth, diffusion controlled with decreasing interface velocity. This is consistent with the hypothesis that the fast reaction is likely to be the presence of Ti2Fe-like secondary phases that act as a gateway for hydrogen.

Automated summary

Adding Zr + V or Zr + V + Mn to TiFe alloy can improve its microstructure and hydrogen storage properties, promoting the occurrence of the first hydrogenation. The presence of secondary phases similar to Ti2Fe acts as a gateway for hydrogen, resulting in fast hydrogenation and high capacity in the alloy. The rate-limiting step in the hydrogenation process is found to be 3D growth, diffusion controlled with decreasing interface velocity.