Effects of Impurity on Ti-Mn-(FeV80) based Alloys and its Properties Recover Mechanism

Adding FeV80 is a cost-effective method to enhance the hydrogen storage performance of Ti-Mn based alloys, but its impurity elements may offset these improvements. By comparing the components of different FeV80 alloys, C, Si and Al were identified as the main impurity elements. To evaluate the effects of these impurities, different mass fractions of C, Si, and Al (0.05,0.1,0.2,0.5,1.0 wt%) were doped into Ti0.9Zr0.1Mn1.42V0.41Fe0.09 alloys and their hydrogen storage performances were tested. Among them, Al exerts the most adverse effect on hydrogen storage capacity, while C and Si show beneficial effects when at low addition amounts. Furthermore, different mass fractions La, Y and Ce (0.01, 0.02 and 0.03 at%) were introduced to purify FeV80 alloys, and then Ti0.9Zr0.1Mn1.42(FeV80)0.41 alloys were prepared using these purified FeV80 master. The Results show that rare earth doping can effectively recover the hydrogen storage capacity of Ti-Mn based alloys. Specifically, the hydrogen storage capacity of Ti0.9Zr0.1Mn1.42(FeV80)0.41Ce0.03 recovered to 1.95 wt%, which is comparable to that of the original alloy. Finally, the property recovery mechanism was investigated. It was found that rare earth elements can effectively remove Al and its oxides, leading to the recovery of the hydrogen storage performance of Ti-Mn based alloys.