1. Initial oxidation of Fe–Cr alloys: in situ STM and ex situ SEM observation
- Author
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Eung Yeul Park, Boris Hüning, Michael Spiegel, Michael Rohwerder, and Sergiy Borodin
- Subjects
In situ ,Materials science ,Mechanical Engineering ,Metallurgy ,Metals and Alloys ,Oxide ,Nucleation ,Partial pressure ,Condensed Matter Physics ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,X-ray photoelectron spectroscopy ,Mechanics of Materials ,Materials Chemistry ,Ceramics and Composites ,Crystallite ,Layer (electronics) ,Single crystal - Abstract
In order to understand the initial oxidation of Fe–Cr alloys a single crystal of Fe–15Cr (100) was oxidized at 440°C under controlled oxygen partial pressure in a UHV system and the surface morphology was observed using in situ STM (basic pressure 1×10−10 mbar); in addition, polycrystalline Fe&15Cr was oxidized at 400°C in an IR-furnace in atmospheric air and the morphology was observed using ex situ SEM. The chemistry of the surface oxide layers was studied by XPS.Preparation of the single crystal in the UHV system did not lead to segregation of Cr to the surface during heating. In situ STM investigation showed that oxidation of Fe–Cr commenced by nucleation of Cr oxide on the surface, due to selective oxidation of Cr. When the Cr at the surface and at the interface was completely consumed by nucleation of Cr oxide, Fe oxidized and covered the initial Cr oxide nuclei, resulting in an Fe oxide layer on the surface. Ex situ experiments showed that initial oxidation of the mechanically prepared poly...
- Published
- 2005
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