Investigation of hydrogen absorption/desorption properties of ZrMn0.85−xFe1+x alloys

The crystal structures and hydrogen absorption/desorption properties of the ZrMn0.85−xFe1+x alloys (x = 0, 0.2, 0.4) were investigated systematically. The pressure–composition (PC) isotherms and absorption kinetics were measured at 273–333 K by the volumetric method. Besides the crystal structure, the plateau pressure and the hydrogen intake capacity, this article also discussed the absorption kinetics, the pulverization resistance and the thermodynamic properties. XRD patterns revealed that ZrMn0.85Fe and ZrMn0.65Fe1.2 were formed as hexagonal C14 laves phase structure while ZrMn0.45Fe1.4 possessed cubic C15 laves phase structure. With the increase of Fe and decrease of Mn, the plateau pressure increased while the hydrogen intake capacity lowered and the hydrogen absorption kinetics degraded. On the other hand, the hysteresis alleviated, the pulverization resistance improved and the stability of the hydrides decreased. The decomposition pressure was increased to more than 160 times for ZrMn0.85Fe and more than 2500 times for ZrMn0.65Fe1.2 compared with that of the ZrMn2 alloy.