Study of Mg-M (M = Co, Ni and Fe) mixture elaborated by reactive mechanical alloying: hydrogen sorption properties

Reactive Mechanical Alloying (MA in H-2) Of magnesium powder allows to obta in partial conversion of Mg to MgH2. The ratio MgH2/Mg can be improved by i ncreasing the milling time or by adding a 3d-element (with the same initial particle size). X-ray diffraction was applied successfully to determine th e quantity of MgH2 formed. The RMA allows to suppress the activation proced ure generally requested for magnesium. The hydriding is determined to be a two step process: first nucleation and then diffusion. A direct relationshi p exists between the nucleation duration and the specific surface. It is de monstrated that RMA for short time (2 h) is an effective way to strongly im prove the hydrogen storage properties of both magnesium and (Mg + 10 wt% M) mixtures. (C) 2001 International Association for Hydrogen Energy. Publishe d by Elsevier Science Ltd. All rights reserved.