Improving the dynamics of a Nd-Mg-Ni-based alloy by combining Ni element and mechanical milling

To improve the reversible kinetics and electrochemical performance of a Nd-Mg-Ni-based alloy, NdMg 11 Ni + x wt% Ni ( x = 100 or 200) samples were prepared through combining the addition of Ni element and ball-milling technology. Meanwhile, the effects of the addition of Ni element and the duration of milling on the NdMg 11 Ni samples were researched. The results indicate that the addition of Ni element has a beneficial effect on the dynamics of the samples. Meanwhile, the milling duration also has a beneficial effect on the high-rate discharging capabilities, the gaseous hydrogenation rate, and the dehydrogenation dynamics. When the ball-milling time is increased from 5 h to 60 h, the value of R d 20 (the ratio of the dehydrogenation capabilities within 20 min to the saturated hydrogenation capabilities) is raised from 62.20% to 71.59% for the x = 200 sample, and from 58.03% to 64.81% for the x = 100 sample; this is believed to be due to a decline in the activation energy resulting from an increase in the Ni content and ball-milling time. In addition, the E a value of NdMg 11 Ni + 200 wt% Ni with a ball-milling time of 60 h is 55.7 kJ mol −1 . Both ball grinding and increasing the nickel content can effectively reduce the dehydrogenation activation energy of a RE-Mg-based alloy.