The influence of a reactive element on the growth of a thermally grown chromia scale : a grazing emission x-ray fluorescence study.
The oxidation of 55Fe-25Cr-20Ni (wt.%) alloys, with and without added reactive element (RE) Y, were studied using grazing-emission X-ray fluorescence (GEXRF). Samples were studied after isothermal treatments at 750 C in O2 and after cyclic-oxidation treatments. In early-stage oxidation, a Ni-rich scale is formed. The distribution of this early-stage Ni deposit is studied as the scale evolves. The Ni deposit, serving as a marker, remains on the outer scale surface in Y-containing alloys, but is not detectable in scales on Y-free alloys. The results indicate that new chromia scale growth occurs at the outer surface in Y-free alloys but, for Y-containing alloys, new growth occurs away from the outer surface. Thus, a shift in the growth mode is apparently observed at 750 C, consistent with higher-temperature observations. However, unlike the high-temperature measurements, scale-growth rates are not significantly affected by the RE.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 949301
- Report Number(s):
- ANL/MSD/JA-39755; OXMEAF; TRN: US201012%%99
- Journal Information:
- Oxid. Met., Vol. 59, Issue 5-6 ; Jun. 2003; ISSN 0030-770X
- Country of Publication:
- United States
- Language:
- ENGLISH
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