Investigations on synthesis and hydrogenation properties of Mg–20 wt% Ni–1 wt% TiO2 composite prepared by reactive mechanical alloying

Reactive mechanical alloying (RMA) was used to prepare Mg–20 wt% Ni–1.0 wt% TiO2 composite materials. A nanocrystalline composite of MgH2 and Mg2NiH4 formed after 60 h of ball-milling. An increase of the nanocrystalline size was found after 20 hydriding/dehydriding cycles. It absorbed more than 80% of its full capacity in the temperature range of 363–543 K within less than 1 min and desorbed 3.22 mass% of hydrogen at 578 K under a hydrogen pressure of 0.1 MPa in 1 h. DSC analysis shows that the thermodynamic property of Mg-based hydrogen storage alloys do not be changed by the addition of TiO2 and ball-milled process.