Improving the hydrogen absorption properties of commercial Mg–Zn–Zr alloy

Commercial alloy ZK60 (Mg-6 wt%Zn-0.8 wt% Zr) was used as a hydrogen-storage material to study the effect of cold rolling, ball milling, and plus graphite additives on hydrogen-storage characteristics, hydrogen absorption–desorption behavior, and the related microstructural change of the alloy. Experimental results showed that cold-rolled alloy could not be activated easily. Even after ball milling for 20 h and hydrogen absorption–desorption cycling for 10 times, no saturated hydrogen absorption was observed for cold-rolled alloy. In contrast, alloys with 5 wt% graphite additives could be easily activated after the first hydrogen absorption–desorption cycle, and a saturated hydrogen absorption of 6.9 wt% was obtained after absorption–desorption cycling for five times. A hydrogen absorption of 5.52 wt%, equivalent to 80% of the saturated absorption amount, was measured in 5 min, showing a hydrogen absorption rate of 1.104 wt%/min. The sample reached saturation in 30 min.