Dresden 2011 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 42: Functional Materials I

MM 42.4: Vortrag

Donnerstag, 17. März 2011, 18:30–18:45, IFW B

Hydrogen absorption behavior of nano-crystalline Mg thin films — •Helmut Takahiro Uchida, Reiner Kirchheim, and Astrid Pundt — Institut fuer Materialphysik, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen, Germany

In-situ XRD measurements of hydrogen absorption behavior were done for nano-crystalline Mg thin films at room temperature. 20 nm Pd-capped nanocrystalline Mg films of different thicknesses were prepared in an UHV chamber, by means of ion beam sputter deposition under Ar-atmosphere at the pressure of 2,2*10E-4 mbar. The Mg films were deposited on Si (100) substrates. XRD measurements using a Phillips X-Pert diffractometer with Co-K alpha radiation were performed before and after hydrogenation in order to check the phase transition and the change of the sample texture. In-situ XRD measurements have been done at the HASYLAB synchrotron facility in Hamburg and at European Synchrotron Facility in Grenoble. Changes of the resistivity during hydrogenation were also monitored by four-point measurement, during electrochemical- and gas pressure hydrogen loading. The diffusion coefficient of hydrogen in nano-crystalline Mg thin films at room temperature is estimated from in-situ synchrotron XRD measurements and compared with the results of electrochemical hydrogen permeation measurements. The impact of grain boundaries on the hydrogenation properties is discussed. Financial support by the DAAD, HASYLAB and the ESRF is gratefully acknowledged.