Oxidation behavior of iron-chromium alloys at elevated temperatures: A reactive-element effect
Oxidation tests were conducted on samples of Fe-25Cr, Fe-25Cr,-0.3-1.0Y, and Fe-25Cr-1Ce at temperatures of 700 to 1000{degrees}C and oxygen partial pressures of 1 to 20 atm for time periods of 19 to 160 h. In some tests, oxidized samples were quenched from test temperature to room temperature in {approximately}20 min to examine characteristics of the spallation scales. The results showed that the scales, even though of the same composition, spalled totally when developed on Fe-25Cr alloy, while those on Ce- and Y-containing alloys exhibited good scale adherence and no spallation. After removal of the spalled scales, specimens of Fe-25Cr alloy were reoxidized to gain insight into development and morphology of thermally grown scales and their spallation characteristics. The reoxidized samples formed complex scale layers that had iron oxide phase at the gas side of the interface; the scale layer was adherent and no spallation was noted. Experiments were conducted to evaluate the roles of alloy grain size and grain growth rate in development and spallation of oxide scales. Results showed that excessive alloy grain growth is the primary cause of spallation of thermally grown scales. Additions of reactive elements such as Y and Ce minimize alloy grain growth and thus improve the adhesion of scales to the substrate and virtually eliminate spallation.
- Research Organization:
- Argonne National Lab., IL (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 10160023
- Report Number(s):
- ANL/FE--92/1; ON: DE92017143
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360105
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201
CERIUM
CHEMICAL AND PHYSICOCHEMICAL PROPERTIES
CHEMICAL REACTION KINETICS
CHROMIUM ALLOYS
CORROSION AND EROSION
CORROSION RESISTANCE
GRAIN SIZE
IRON ALLOYS
IRON OXIDES
OXIDATION
OXYGEN
PARTIAL PRESSURE
PHASE STABILITY
SCANNING ELECTRON MICROSCOPY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
THERMAL GRAVIMETRIC ANALYSIS
YTTRIUM