Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5459496 | Journal of Alloys and Compounds | 2017 | 7 Pages |
Abstract
Mg(HxF1âx)2 solid solutions have been synthesized by mechanical milling MgF2 and MgH2 under H2 atmosphere. Complete solubility has been observed at 475 °C. The solid solution presents a rutile-type structure with the anion site randomly occupied by Hâ or Fâ and with lattice parameters showing positive deviations from Vegard's law. The solution can be decomposed and re-formed reversibly by changing H2 pressure. For example, Mg(H0.9F0.1)2 reversibly stores 5.5 wt. % H2 in less than 3 min at 440 °C. During decomposition H2 is released, and Mg and a solution rich in F appear as products. This process takes place in two clearly marked stages controlled by Fâ concentration in the material. The decomposition enthalpy of the first one is close to that of MgH2 for Mg(H0.9F0.1)2, and decreases with the H content in the solution.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
S.A. Pighin, G. Urretavizcaya, F.J. Castro,