Reactive Milling of Magnesium under Hydrogen Using Transition Metals and their Fluorides as Additives
Magnesium is light, abundant and it can store up to 7.6 wt. % of hydrogen forming MgH2 and accordingly it is a promising material for hydrogen storage. Processing of Mg-based mixtures by high-energy ball milling (HEBM) can produce materials with high level H-sorption properties. In the present report, we display and compare the effects of different nanocrystalline additives (MgF2, Fe, NbH0,89, FeF3, VF3) on the formation of MgH2 by reactive milling. The H-desorption behavior of the as-prepared nanocomposites is also evaluated. A combined catalytic effect is observed due to the synergic action of MgF2 and Fe (or NbH0,89) on the hydrogenation rate during processing. The transition metal fluorides promote as well the MgH2 synthesis. By using more energy-intensive milling conditions and adequate additives in given proportions (e.g. 5 mol. % FeF3), is shown to be very effective for a full and fast synthesis (4 h) of MgH2 by reactive milling.
Yuriy Verbovytskyy and António Pereira Gonçalves
D. R. Leiva et al., "Reactive Milling of Magnesium under Hydrogen Using Transition Metals and their Fluorides as Additives", Solid State Phenomena, Vol. 194, pp. 232-236, 2013