Dresden 2017 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 8: Topical session: Interface-Controlled Microstructures: Mechanical Properties and Mechano-Chemical Coupling - Segregation and Embrittlement II

MM 8.2: Talk

Monday, March 20, 2017, 12:00–12:15, BAR 205

Defect generation in Palladium by Hydrogen loaded Niobium layers — •Vladimir Burlaka, Vladimir Roddatis, Marian Bongers, and Astrid Pundt — Institut für Materialphysik, Universität Göttingen, Germany

In this paper, we use layers with high hydrogen affinity to influence the defect structure of an overlaying catalytic layer. It will be shown that pre-existing defects can be healed out by a low-pressure hydrogen treatment and, opposite, additional defects can be generated by a higher pressure treatment. In our study Pd/Nb/Al2O3 double layers are studied during hydrogen gas exposure at room temperature by using Scanning Tunneling Microscopy (STM), X-ray diffraction (XRD) and environmental transmission electron microscopy (ETEM). [1] STM results show hydrogen-induced topography changes at the Pd/Nb interface. The XRD measurements demonstrate that the topography changes in the Nb-H film result in microstructural changes in the overlaying Pd layer. ETEM measurements on cross-cut lamellas show that the modification of the Pd top-layer occurs due to the precipitation and growth of the hydride phase within the Nb underlying film: generation of new defects and interface roughening are observed. We conclude that these changes in the Pd layer can be varied by changing the Nb-film thickness. [2]

Financial support by the DFG via PU131/9 and PU131/12 and the beamtime provided by DESY and ESRF are acknowledged. [1] V.Burlaka, S.Wagner, M.Hamm, A.Pundt, Nano Letters 16 (2016) 6207. [2] V.Burlaka, V.Roddatis, M.Bongers, A.Pundt, submitted.