Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 51: Metal Substrates: Adsorption III
O 51.6: Vortrag
Donnerstag, 29. März 2007, 12:30–12:45, H39
The influence of surface oxides on the hydrogen absorption behaviour of metal hydride alloys — •Mark Schülke1, Hubert Paulus2, Martin Lammers2, Gabor Kiss3, and Karl-Heinz Müller1,2 — 1University of Applied Sciences of South Westphalia, Luebecker Ring 2, 59494 Soest, Germany — 2Institute for Technology and Knowledge Transfer (TWS), Luebecker Ring 2, 59494 Soest, Germany — 3Technical University of Budapest, Institute of physics, Chair of atom physics, H-1111 Budapest, Budafoki ut 8, Hungary
Metal hydride alloys are one promising alternative for hydrogen storage. However the influence of their surface on the hydrogen absorption process is not yet understood in detail. Oxygen adsorption from the gas phase as well as oxygen segregation and the segregation of alloy components play an important role in the hydrogen absorption process. The presented investigations are part of a series of experiments dealing with these subjects.
The presented experiments deal with the influence of adsorbed oxygen on the surface composition and the absorption behaviour of a AB2 Laves phase alloy, namely Ti0.95Zr0.05Mn1.53V0.47Fe0.08Al0.02. In order to examine this, the samples were exposed to different doses of oxygen (e.g. 100 L, 1000 L) and analyzed by XPS and SNMS. It is shown that all main alloy components (Ti, Mn, V) are oxidized to certain oxidation states. Also a Mn enrichment at the surface can be observed (oxygen-induced segregation). The influence of these effects on the hydrogen absorption behaviour (capacity, dynamics) is discussed, too.