Dresden 2009 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 49: Hydrogen in Metals

MM 49.2: Vortrag

Freitag, 27. März 2009, 10:30–10:45, IFW D

Hydrogenation Behaviour of Titanium Thin Films — •Ervin Tal-Gutelmacher, Ryota Gemma, Astrid Pundt, and Reiner Kirchheim — Institute for Materials Physics, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen

Titanium films of different thicknesses were prepared on sapphire substrates in an UHV chamber, by means of ion beam sputter deposition under Ar-atmosphere at the pressure of 1,5*10E-4 mbar. For electrochemical hydrogen loading, the films were covered by a 30 nm thick layer of Pd in order to prevent oxidation and facilitate hydrogen absorption. In-situ stress measurements were conducted during step-by-step electrochemical hydrogen charging of the films. XRD measurements using a Phillips X-Pert diffractometer with a Co-Kα radiation were performed before and after hydrogenation in order to investigate the effect of hydrogen loading on the microstructure. The phase boundaries, as well as the stress and strain development during hydrogen absorption, depend strongly on the crystallographic growth orientation of the films. The main characteristics of absorption behaviour of hydrogen, as well as the thermodynamics and phase boundaries of titanium-hydrogen thin films are discussed in detail with specific emphasis on the comparison to titanium-hydrogen bulk system. Shifted grain boundaries and narrowed two-phase field appear in Ti-H film system, which are mainly attributed to the microstructural contribution, as well as to the large stresses in the GPa-range that built up between the films and their substrate.