Structure transformations and hydrogen storage properties of co-sputtered MgNi films

• Published in: Applied surface science 2009-03, Vol.255 (11), p.5971-5974
• Main Authors: Pranevicius, L., Wirth, E., Milcius, D., Lelis, M., Pranevicius, L.L., Bacianskas, A.
• Format: Article
• Language: English
• Subjects: Chemical composition analysis, chemical depth and dopant profiling; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Exact sciences and technology; Hydrogen storage; Materials science; Materials testing; Methods of deposition of films and coatings; film growth and epitaxy; MgNi films; Phase transitions and critical phenomena; Physics; Solid surfaces and solid-solid interfaces; Structure; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2009.01.047

The quantity of accommodated and distribution profiles of hydrogen in 1.5-μm thick co-sputtered MgNi films after uptake of hydrogen at 800 kPa pressure within the temperature range 200–250 °C during 1 h, 3 h, 6 h and 72 h are measured. The occurring phase changes are followed by X-ray diffraction measurements at room temperature. We conclude that the hydrogenation process involves two stages: (i) the fast nucleation of the initial Mg 2NiH 4 layer near the substrate interface and (ii) the slow random nucleation of the same phase within the remaining part of the film. The growth of the initial hydride layer may be blocked by the surface oxide barrier layer formed during hydrogenation. We find that hydrogen-induced structural transformations are correlated with oxygen contamination and modify hydrogen storage properties.