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

J. A. PUSZKIEL; P. ARNEODO LAROCHETTE; F. C. GENNARI

JOURNAL OF ALLOYS AND COMPOUNDS

Elsevier

Lugar: Amsterdam; Año: 2008 vol. 463 p. 134 - 142

0925-8388

The transition metal complex hydride Mg2FeH6 has been successfully synthesized utilizing mechanical milling of a 2Mg?Fe mixture followed by heating at 673K under 6MPa of hydrogen pressure, without pressing step. The obtained yield of Mg2FeH6 was about 50%. Hydrogen storage properties of the Mg?Fe?H system, i.e. capacities, absorption/desorption kinetics and thermodynamic parameters, were examined. The pressurecomposition isotherm (PCI) measurements of the samples at 548?673K 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 573K 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.