Oxidation behavior of Cr-Cr{sub 2}Nb alloys
Oxidation of hypoeutectic Cr-Cr{sub 2}Nb alloys containing 6 and 12% Nb at 950 C resulted in formation of a multiproduct scale consisting of a continuous Cr{sub 2}O{sub 3} outer layer and an inner region of discrete CrNbO{sub 4} products interspersed with Cr{sub 2}O{sub 3}. Overall oxidation behavior resembled that of Cr as reactions with the Cr-rich phase tended to dominate. Oxidation resistance, in terms of reaction kinetics and scale adherence, increased with increasing volume fraction of the Cr-Cr{sub 2}Nb eutectic phase. A model for the oxidation of these alloys based on the growth of Cr{sub 2}O{sub 3} on the Cr-rich matrix regions and the formation of a slower growing CrNbO{sub 4} on the Cr{sub 2}Nb-enriched phase can qualitatively explain the development of the multiproduct scale and the observed gravimetric and spallation results. Possible microstructural/compositional modifications to improve oxidation resistance are suggested.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 459972
- Report Number(s):
- CONF-961040--21; ON: DE97003607
- Country of Publication:
- United States
- Language:
- English
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