Thermal stabilization and hydrogen storage properties of Mg–40 wt% composite prepared by mechanical milling

The thermal stability and hydrogen storage properties of Mg–40wt% Ti 0.28 Cr 0.50 V 0.22 prepared by mechanical milled for 40 h under 2.0 hydrogen pressure were investigated. The experimental results showed that the composite is easily activated, and exhibits good hydrogen sorption properties. It can absorb nearly 90% hydrogen of the total capacity in 1 min, and the maximum hydrogen absorption capacity reaches to 3.2, 3.5 and 4.0 wt% at 298, 368 and 548 K in 10 min, respectively. DSC measurement results showed that hydrogen desorption temperature of composite is depressed about 150 K compared with that of pure MgH 2 . However, if the composite was heated over 620 K, the hydrogen desorption temperature was elevated to the same temperature as that of pure MgH 2 due to the re-crystallization or growth of the nano-structure Mg, although the hydrogen adsorption kinetic were not obviously affected. Therefore, It can be deduced that nano-structure Mg phase is the main reason for decreasing the hydrogen desoprtion temperature. The nano-structure Ti 0.28 Cr 0.50 V 0.22 phase plays a more important role in improving hydriding kinetics of composite.