Effect of Milling Time and 25Ce-75Ni Addition on Hydrogen Desorption Properties of Magnesium Hydride-based Composite Produced by Mechanical Alloying

In this study, the composite material with composition of MgH2-10 wt% (25Ce-75Ni) has been prepared by co-milling of magnesium hydride powder with Ce-Ni alloy produced by vacuum arc remelting method. The effect of milling time and additive on magnesium hydride structure, i.e. crystallite size, lattice strain and particle size, and also hydrogen desorption properties of obtained composite were evaluated and compared with pure milled MgH2. It has been shown that the addition of 25Ce-75Ni alloy to magnesium hydride yielded a finer particle size. As a consequence, the desorption temperature of mechanically activated MgH2 decreased from 340 °C to 280 °C for composite 1(5 h mechanical alloying) and to 290 °C for composite 2 (15 h mechanical alloying). Further improvement in the hydrogen desorption tempreture of composite 1 can be related to finer particle size and higher Mg2NiH4 phase value, which corresponded with calculated enthalpy results.