The role of Zr and Nb in oxidation/sulfidation behavior of Fe-Cr-Ni alloys

Technical Report · Thu Nov 01 00:00:00 EST 1990

DOI:https://doi.org/10.2172/6281516· OSTI ID:6281516

Natesan, K ^[1]; Baxter, D J ^[2]

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1. Argonne National Lab., IL (USA)
2. Argonne National Lab., IL (USA) INCO Alloy Ltd., Hereford, England (UK)

05Structural Fe-Cr-Ni alloys may undergo rapid degradation at elevated temperatures unless protective surface oxide scales are formed and maintained. The ability of alloys to resist rapid degradation strongly depends on their Cr content and the chemistry of the exposure environment. Normally, 20 wt % Cr is required for service at temperatures up to 1000{degree}C; the presence of sulfur, however, inhibits formation of a protective surface oxide scale. The oxidation and sulfidation behavior of Fe-Cr-Ni alloys is examined over a wide temperature range (650 to 1000{degree}C), with particular emphasis on the effects of alloy Cr content and the radiation of reactive elements such as Nb and Zr. Both Nb and Zr are shown to promote protective oxidation behavior on the 12 wt % Cr alloy in oxidizing environments and to suppress sulfidation in mixed oxygen/sulfur environments. Additions of Nb and Zr at 3 wt % level resulted in stabilization of Cr{sub 2}O{sub 3} scale and led to a barrier layer of Nb- or Zr-rich oxide at the scale/metal interface, which acted to minimize the transport of base metal cations across the scale. Oxide scales were preformed in sulfur-free environments and subsequently exposed to oxygen/sulfur mixed-gas atmospheres. Preformed scales were found to delay the onset of breakaway corrosion. Corrosions test results obtained under isothermal and thermal cycling conditions are presented. 58 refs., 55 figs., 8 tabs.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: DOE/FE
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6281516
• Report Number(s): ANL/FE-90/2; ON: DE91005749
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM ALLOYS
CORROSION
IRON BASE ALLOYS
NICKEL ALLOYS
NIOBIUM ALLOYS
METALLURGICAL EFFECTS
ZIRCONIUM ALLOYS
CHROMIUM OXIDES
HEAT TREATMENTS
MANGANESE ADDITIONS
MICROSTRUCTURE
NIOBIUM ADDITIONS
OXIDATION
SCALING
SILICON ADDITIONS
SULFIDATION
ZIRCONIUM ADDITIONS
ALLOYS
CHALCOGENIDES
CHEMICAL REACTIONS
CHROMIUM COMPOUNDS
CRYSTAL STRUCTURE
IRON ALLOYS
MANGANESE ALLOYS
OXIDES
OXYGEN COMPOUNDS
SILICON ALLOYS
TRANSITION ELEMENT COMPOUNDS
360105* - Metals & Alloys- Corrosion & Erosion