Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 96: Solid-Liquid Interfaces IV: Reactions and Electrochemistry
O 96.11: Vortrag
Donnerstag, 21. März 2024, 17:45–18:00, TC 006
Computational chemistry analysis of passive layer formation and breakdown mechanisms in ferritic stainless steels — •Vahid Jamebozorgi1,2, Karsten Rasim3, and Christian Schröder1,2 — 1Bielefeld Institute for Applied Materials Research, Bielefeld University of Applied Sciences and Arts, 33619 Bielefeld, Germany — 2Faculty of Physics, Bielefeld University, 33615 Bielefeld, Germany — 3Miele \& Cie. KG, Center for Materials (CFM), Carl-Miele-Straße 29, 33332 Gütersloh
Despite extensive research on passive layer formation and breakdown, several questions still remain unanswered. These include the reasons behind the bilayer nature of the passive layer, the decrease in hydrogen and oxygen diffusivity upon entering the passive layer, the underlying mechanisms of passive layer formation and breakdown, and the influence of microstructure on passive layer formation and function in stainless steels. In this study, we employed ReaxFF molecular dynamics to investigate passivation and depassivation of stainless steel in a polycrystalline structure. Through static and dynamic calculations, we elucidated the mechanisms of passive layer formation, which were primarily governed by clustering. Our analysis also highlighted the significant role of hydrogen diffusion and its reaction with metallic compounds in depassivation. We have identified several physical phenomena involved in the processes of passivation and depassivation, which can provide explanations for the aforementioned unresolved points.
Keywords: Stainless steel corrosion; Passivation; ReaxFF modeling; Microstructure