Formation of corrosion pockets in FeNiCrAl at high temperatures investigated by 3D FIB‐SEM tomography
- A recently published study of high temperature nitridation of iron chromium aluminum alloys (FeCrAl) at 900°C in N2–H2 has redundantly shown the formation of locally confined corrosion pockets reaching several microns into the alloy. These nitrided pockets form underneath chromia islands laterally surrounded by the otherwise protective alumina scale. Chromia renders a nitrogen‐permeable defect under the given conditions and the presence of aluminum in the alloy. In light of these findings on FeCrAl, a focused ion beam–scanning electron microscope tomography study has been undertaken on an equally nitrided FeNiCrAl sample to characterize its nitridation corrosion features chemically and morphologically. The alloy is strengthened by a high number of chromium carbide precipitates, which are also preferential chromia formation sites. Besides the confirmation of the complete encapsulation of the corrosion pocket from the alloy by a closed and dense aluminum nitride rim, very large voids have been found in the said pockets. Furthermore, metallic particles comprising nickel and iron are deposited on top of the outer oxide scale above such void regions.
Author: | Katrin JahnsORCiD, Ulrich Krupp |
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Title (English): | Formation of corrosion pockets in FeNiCrAl at high temperatures investigated by 3D FIB‐SEM tomography |
DOI: | https://doi.org/10.1002/maco.201911386 |
ISSN: | 1521-4176 (online); 0947-5117 (print) |
Parent Title (English): | Materials and Corrosion |
Publisher: | WILEY-VCH Verlag GmbH & Co. KGaA |
Place of publication: | Weinheim |
Document Type: | Article |
Language: | English |
Year of Completion: | 2019 |
Release Date: | 2020/07/30 |
Tag: | FIB-SEM tomography; FeNiCrAl; nitridation; void formation |
Page Number: | 9 |
Note: | Open Access |
Faculties: | Fakultät IuI |
DDC classes: | 600 Technik, Medizin, angewandte Wissenschaften / 620 Ingenieurwissenschaften und Maschinenbau |
Review Status: | Veröffentlichte Fassung/Verlagsversion |
Licence (German): | ![]() |