Hydrogen Sorption Kinetics in MgH2 and TiH2 Thin Films

Efi Hadjixenophontos; Lukas Michalek; Andreas Weigel; Guido Schmitz

doi:10.4028/www.scientific.net/DDF.383.127

Paper Titles

Effect of Equal Channel and Dynamic Channel Angular Pressing of Ni and Further Heat Treatment on its Structure and Grain Boundary Diffusion
p.96

Effect of Atomic Complexes Formation in Grain Boundaries on Grain Boundary Diffusion
p.103

Mullins' Self-Similar Grooving Solution Revisited
p.112

The Role of Interfaces in Evolution of Structure and Thermal Stability of Cu-Nb Composite Processed by High-Pressure Torsion
p.118

Hydrogen Sorption Kinetics in MgH₂ and TiH₂ Thin Films
p.127

On the Mechanism of Oxidation Resistance of W-Cr-Pd Alloys
p.133

In Situ XRD Experiments on the Growth of Expanded Austenite Using Different Process Gases
p.142

Oxidation Kinetics of Nitrogen Doped TiO_2-δ Thin Films: Analysis on the Basis of Oxygen Activity Dependence of the Chemical Diffusion Coefficient
p.147

Properties of Species Profiles during Oxygen Chemical Diffusion in Oxides
p.153

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Hydrogen Sorption Kinetics in MgH₂ and TiH₂ Thin Films

Abstract:

The diffusion mechanism of H in metals and metal hydrides is studied particularly at high H₂ pressures. Thin films of Mg and Ti offer a convenient tool to quantify the atomic transport. We show how different parameters of hydrogenation affect the kinetics. At 200°C, the Pd-Mg interface is predominant and a linear regime of hydrogenation is observed, whereas at 300°C a parabolic regime is detected. In Mg, the hydride forms from the surface to the substrate whereas in Ti growth of TiH₂ starts from the substrate. A linear kinetics is seen during hydrogenation of Ti films, which is due to the oxide layer on top, measured to be about 10nm thick. In the studied high pressure regime, the hydrogenation is not pressure dependent any more. Quantitative calculation of the growth rate and the diffusion coefficient of H in the hydrides is presented.