Effect of regulating the different proportions of Zr to Mn elements on the hydrogen storage properties of titanium–iron–manganese–hydrogen storage alloys

Abstract

The effect of regulating the different proportions (0, 1 : 3, 1 : 2 and 1 : 1) of Zr to Mn elements on the hydrogen storage properties of TiFe_0.85−xMn_0.15Zr_x (x = 0, 0.05, 0.075 and 0.15) alloys was systematically studied in this work. The results showed that all alloys mainly showed TiFe and MgZn₂ type phases. The MgZn₂ type phase went up with the proportion of Zr to Mn elements. At the same time, increasing the proportion of Zr to Mn elements enhanced the first hydrogenation properties. In addition, the x = 0.15 alloy showed the highest hydrogen storage capacity during the first hydrogenation process. This was because the MgZn₂ type phase could improve the penetration of hydrogen atoms and enhance the diffusion of hydrogen atoms. During the test of prolonged air exposure, it was clear that the oxidation resistance also increased with the proportion of Zr to Mn elements. In addition to this, the effect of the starting particle size was also studied. When the length of the starting particle size was around 0.5 cm, the x = 0.05 alloy did not absorb any hydrogen within 1500 seconds. However, the x = 0.15 alloy could be activated in only around 100 seconds. Finally, the rate limiting step of the first hydrogenation and PCT properties were also investigated.