Effect of V, Nb, Ti and graphite additions on the hydrogen desorption temperature of magnesium hydride

In this study the effects of mechanical milling with 5 wt.% of additives (V, Nb, Ti and Graphite) on the hydrogen desorption temperature of the magnesium hydride (MgH2) were studied. The powder mixtures were mechanically milled for 2 h. X-ray diffraction (XRD), scanning electron microscope (SEM), and optical microscope (OM) techniques were used for the structural and morphological characterization of powders. Differential scanning calorimeter (DSC) was used to investigate the effects of the mechanical milling with additives on the hydrogen desorption temperature of the magnesium hydride powder. DSC results show that the hydrogen desorption temperatures of mechanically milled MgH2 with additives are depressed about ∼40–50 °C compared with that of as-received MgH2. The particle size analysis results indicate that decrease of the particle size of powders leads to a decrease of the hydrogen desorption temperature. Moreover, increasing specific surface area can also contribute to a decrease on the hydrogen desorption temperature.