Synthesis of Mg2FeH6 by reactive mechanical alloying:: formation and decomposition properties

The Mg2FeH6 hydride was synthesized by reactive mechanical alloying (RMA) in a single process from Mg and Fe elemental powders in a hydrogen atmosphere at room temperature. The formation of Mg2FeH6 involves two steps: MgH6 formation at shorter milling times, and reaction between MgH2 and Fe to produce Mg2FeH6 as milling time increases. On the contrary, the decomposition of Mg2FeH6 occurs in only one step, giving the elemental metals and hydrogen gas as reaction products. The presence of Fe in the mixture also produces a catalytic effect on hydrogen desorption kinetics from MgH2. This is evidenced by a reduction of the decomposition temperature in more than 100 degreesC. (C) 2002 Elsevier Science B.V. All rights reserved.