Composition at Al{sub 2}O{sub 3}/FeCrAl interfaces after high temperature oxidation
Scanning Auger microscopy was used to study the chemistry of Al{sub 2}O{sub 3}/FeCrAl interfaces after the oxide scale had been removed in ultra high vacuum. Past studies that examined impurity segregation at these interfaces have shown a strong presence of sulfur, along with carbon and chromium enrichments. However, the relationships between these elements and the rate of their build up at the interface have not been addressed. This work examined many areas on several different specimens treated at various oxidation times, temperatures and with different cooling rates. Results showed that the carbon segregated during cooling. Interfacial sulfur and chromium concentrations varied at different locations that were not associated with apparent morphological differences, whether they were undulated ridges or valleys, voids, oxide-imprinted areas, alloy grain boundaries or different alloy grain faces. In most cases, there was a strong co-segregation of sulfur and chromium, although no sulfide particles were observed using scanning electron microscopy. At some locations, sulfur was found to segregate without the enrichment of chromium. The sulfur concentration could be low, as in the case of surface segregation in binary systems, or as high as being multi-layered. Results are analyzed in an attempt to recognize the structure of these segregants at the scale/alloy interface, such that their possible effect on scale adhesion may be better understood.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director, Office of Science. Office of Basic Energy Studies. Division of Materials Sciences (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 765468
- Report Number(s):
- LBNL-44784; MTCREQ; R&D Project: 503001; TRN: AH200034%%149
- Journal Information:
- Materials and Corrosion, Vol. 51, Issue 5; Other Information: PBD: 9 Jan 2000; ISSN 0947-5117
- Country of Publication:
- United States
- Language:
- English
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