Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 14: Transport II: Atomic and ionic transport

MM 14.3: Vortrag

Montag, 7. März 2016, 16:15–16:30, H53

Hydrogen sorption kinetics of titanium hydride thin films — •Lukas Michalek, Efi Hadjixenophontos, and Guido Schmitz — University of Stuttgart, Institute for Materials Science, Heisenbergstrasse 3, 70569 Stuttgart, GERMANY

Titanium hydride has been studied a lot in the last few years because of its impressive hydrogenation kinetics. Transition metals are known to improve hydrogen (H) storage materials and act as catalysts in the diffusion process. Despite the low weight percentage of H it can take (4wt.%), it is a material in which H diffuses very easily and furthermore it's stable in air. In this work, we focus on the H-sorption behavior in thin films of thickness 50-400nm in different conditions. Pure α-Ti samples were deposited by ion beam sputtering on Si substrates. Hydrogenation was studied at different temperatures (RT-300°C) at 1-10 bars of H atmosphere for different duration of time (60-600min) in order to measure the kinetic barriers at the interfaces and diffusion coefficients. Hydrogen sorption was quantified by X-ray Diffraction, TEM was used for microstructural analyses and surface analysis was studied by SEM. A pure δ-TiH2 peak appears in the XRD characterization for samples hydrogenated over 100min at 300°C and 10bars of H. Full dehydrogenation of this material is more challenging because of the stability of the hydride. Also the substrate choice appears to play an important role. Possible reversibility of δ-TiH2 to α-Ti has been studied on magnesium oxide and aluminum oxide. The observed sorption behavior at these conditions will be the focus of this work.