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The Scientific World Journal
Volume 2014, Article ID 190320, 16 pages
Research Article

Thermodynamic Modeling of Hydrogen Storage Capacity in Mg-Na Alloys

Department of Mechanical and Industrial Engineering, Concordia University, 1455 de Maisonneuve Boulevard West, QC, Montreal, Canada H3G 1M8

Received 12 June 2014; Accepted 11 August 2014; Published 14 October 2014

Academic Editor: Edward Mikuli

Copyright © 2014 S. Abdessameud et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Thermodynamic modeling of the H-Mg-Na system is performed for the first time in this work in order to understand the phase relationships in this system. A new thermodynamic description of the stable NaMgH3 hydride is performed and the thermodynamic models for the H-Mg, Mg-Na, and H-Na systems are reassessed using the modified quasichemical model for the liquid phase. The thermodynamic properties of the ternary system are estimated from the models of the binary systems and the ternary compound using CALPHAD technique. The constructed database is successfully used to reproduce the pressure-composition isotherms for MgH2 + 10 wt.% NaH mixtures. Also, the pressure-temperature equilibrium diagram and reaction paths for the same composition are predicted at different temperatures and pressures. Even though it is proved that H-Mg-Na does not meet the DOE hydrogen storage requirements for onboard applications, the best working temperatures and pressures to benefit from its full catalytic role are given. Also, the present database can be used for thermodynamic assessments of higher order systems.