Thermodynamic and kinetic studies of Mg–Fe–H after mechanical milling followed by sintering

• Published in: Journal of alloys and compounds Vol. 463; no. 1; pp. 134 - 142
• Main Authors: Puszkiel, J.A., Larochette, P. Arneodo, Gennari, F.C.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 08.09.2008; Elsevier
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Ball milling; Cross-disciplinary physics: materials science; rheology; Energy; Exact sciences and technology; Fuels; Hydrides; Hydrogen; Hydrogen storage materials; Materials science; Materials synthesis; materials processing; Physics; Sintering; Hydrogen storage materials; Ball milling; Hydrides; Sintering; Hydrogen storage; Reversible processes; Ball mill; Enthalpy; Desorption; Entropy; Mechanical alloying; Iron hydride; Heat treatments; Magnesium hydride; Pressing; Hydrogen storage material; Kinetics
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2007.08.085

The transition metal complex hydride Mg 2FeH 6 has been successfully synthesized utilizing mechanical milling of a 2Mg–Fe mixture followed by heating at 673 K under 6 MPa of hydrogen pressure, without pressing step. The obtained yield of Mg 2FeH 6 was about 50%. Hydrogen storage properties of the Mg–Fe–H system, i.e. capacities, absorption/desorption kinetics and thermodynamic parameters, were examined. The pressure-composition isotherm (PCI) measurements of the samples at 548–673 K showed that the alloys possessed good cyclic stability and reversibility. Enthalpies and entropies of decomposition of the Mg–Fe–H system were evaluated by van’t Hoff plots. The absorption/desorption rates at 573 K were very fast in comparison with the reported data. The non-isothermal desorption of hydrogen was found greatly dependent on the thermal history of the sample.