Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 53: Poster Wednesday: Spins and Magnetism

O 53.2: Poster

Wednesday, September 7, 2022, 18:00–20:00, P4

DFT based analysis of surface reactions of stainless steels through degradation in aqueous media — •Vahid Jamebozorgi and Christian Schröder — Bielefeld University and Bielefeld University of applied science

Stainless steels (SSs) are widely used in industry due to their outstanding mechanical and physical properties plus their durability in corrosive media. The corrosion resistance of SSs is caused by the formation of a thin passive layer which mainly consists of chromium oxides. However, the passive layer makes SSs more vulnerable to localized corrosion including pitting corrosion. Pitting corrosion occurs when the passive layer interacts locally with bond-forming atoms and molecules dissolved in the aqueous media, e.g. halides or hydroxide. However, the process of bond formation, erosion of the passive layer, and consequently the degradation of SSs is still not completely understood. Amongst other parameters, the adsorption energy and work function seem to play a key role in pitting corrosion. The experimental determination of the work function is challenging since the surface texture, crystal defects and impurities can increase or decrease work function value significantly. Here, we show how density-functional theory (DFT) computation techniques can be used to obtain adsorption energies and work function values for different crystallographic orientations on the surfaces of Fe, Cr and Ni. As a result we will provide insight into the degradation mechanisms of SSs surfaces in aqueous media.