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P: Fachverband Plasmaphysik

P 5: Poster Session 1

P 5.26: Poster

Montag, 9. März 2020, 16:30–18:30, Empore Lichthof

Phase forming in the Be-Ti system — •Nicola Helfer¹, Jens Bröder², Nabi Aghdassi¹, Hans Rudolf Koslowski¹, Daniel Wortmann², Stefan Blügel², and Christian Linsmeier¹ — ¹Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung - Plasmaphysik, 52425 Jülich, Germany — ²Forschungszentrum Jülich GmbH, Peter Grünberg Institut and Institute for Advanced Simulation, 52425 Jülich, Germany

As a possible blanket material in a future fusion reactor, phase decomposition processes of Be₁₂Ti, especially at reactor relevant temperatures, need to be understood. Thin film system are used as model system to elucidate temperature driven surface changes with X-ray photoelectron spectroscopy (XPS). XPS data for Be-Ti intermetallic compounds are lacking, therefore a novel fitting method is developed. Chemical shifts of each chemical environment within a phase unit cell are calculated with DFT (full-potential linearized augmented plane wave method, FLEUR code) and using Voigt profiles artificial pure phase spectra are generated. These pure phase spectra are used as eigenfunctions for the fit of experimental obtained data.

Titanium is evaporated on polycrystalline Beryllium, intermetallic phases form through annealing. At intermediate temperatures (starting at 600 K) mainly Be depleted phases form, with increasing temperature Be rich phases dominate. At high temperatures a metallic Be layer settles at the surfaces, shown by accomplishing angle resolved XPS. Possible mechanisms are segregation and diffusion but also phase decomposition, further measurements are needed to understand this.