Synthesis of a Thin Metal Hydride Mg2NiH4 Film on a Nickel Substrate

• Published in: Crystallography reports Vol. 69; no. 1; pp. 93 - 101
• Main Authors: Baraban, A. P., Voyt, A. P., Gabis, I. E., Elets, D. I., Levin, A. A., Zaytsev, D. A.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-02-2024; Springer Nature B.V
• Subjects: Crystallography and Scattering Methods; Diffusion rate; Film growth; Intermetallic compounds; Magnesium; Metal foils; Metal hydrides; Nickel; Physics; Physics and Astronomy; Substrates; Surface and Thin Films; Synthesis; Thermal desorption spectroscopy; Thickness
• ISSN: 1063-7745; 1562-689X
• DOI: 10.1134/S1063774523601259

This work is a continuation of the previous study of the synthesis of intermetallic hydride compound Mg
2
NiH
4
in the reaction between a nickel foil and magnesium hydride MgH
2
in a hydrogen atmosphere at pressures exceeding the decomposition pressures of both MgH
2
and Mg
2
NiH
4
. The synthesis was performed at temperatures of 400 and 475°С. With allowance for the results obtained previously at a temperature 450°С, it was found that, after some incubation time, the thickness of grown Mg
2
NiH
4
film depends linearly on time. During incubation, a sublayer of intermetallic compound MgNi
2
is synthesized. The set of these data validates the previously proposed synthesis mechanism, where the limiting factor is the diffusion entry of nickel atoms with a constant rate over the MgNi
2
sublayer. Based on the analysis of X-ray diffraction (XRD) data, it was concluded that the MgNi
2
sublayer thickness is approximately the same for all three synthesis temperatures. The film growth rates were found for all three temperatures using thermal desorption spectroscopy, and the kinetic parameters of the diffusion of nickel atoms in the sublayer of intermetallic compound MgNi
2
were determined based on these data.