Effect of adding ZrM (M=Fe, Ni) intermetallic compounds on the hydrogen absorption/desorption properties of TiCrV alloy.

In this paper, the effect of intermetallic compounds ZrFe and ZrNi on the microstructure and first hydrogenation kinetic of TiCrV alloy is reported. Samples were synthesized by arc melting separately and then 5% of each intermetallic was co-melt with TiCrV alloy. First hydrogenation of all alloys was performed at room temperature under 2.0 MPa of hydrogen. Kinetics and absorption capacities were measured at room temperature, by using apparatus type sieverts. Results indicate that the addition of the intermetallic has an enhancing effect on the kinetic reaction without further modification of hydrogen storage capacities, going from 3.6 wt.% for as-cast alloy, to 3.61 wt.% for alloys +5 wt.% intermetallic. On the other hand, the structure and microstructural analysis were carried out by X-ray diffraction and scanning electron microscopy, respectively. These results show conservation of the structure in the body-centered cubic, and two additional minor phase formations: C14 laves phase for both alloys, and an additional TiNi phase for the TiCrV + 5% ZrNi alloy. Finally, the thermal stabilization of the sample was determined by using differential scanning calorimetry. The results show two types of hydrides that form trapped in different clamping sites with different energies.