Oxygen exchange in oxidation of an Fe-20Cr-10Al alloy in {approximately}10 mbar O{sub 2}/H{sub 2}O-gas mixtures at 920{degrees}C

Journal Article · Sat Feb 01 04:00:00 EST 1997 · Oxidation of Metals

DOI:https://doi.org/10.1007/BF01682374· OSTI ID:468390

Akermark, T; Hultquist, G ^[1]

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1. Royal Institute of Technology, Stockholm (Sweden)

The oxidation of an alumina-forming Fe-20Cr-10Al alloy was studied in situ. The gas-phase components in isotopically labeled {approximately}10 mbar O{sub 2}/H{sub 2}O-gas mixtures were measured from a virtually closed system at 920{degrees}C. Oxidation rates and oxygen-exchange rates were measured and related to each other. From the exchange rates the dissociation rates of O{sub 2} and H{sub 2}O were calculated. These dissociation rates were in the early stage of oxidation found to be the same as the oxidation rate. The rate of oxygen exchange with the oxide can exceed the oxidation rate. From this follows that in analysis of a two-stage oxidation in {sup 16,16}O{sub 2}/{sup 18,18}O{sub 2} the exchange rate of O between the oxide and gas phase has to be considered. The oxides formed in H{sub 2}O containing gas had a H/O-ratio of {approximately}0.1. Vacuum annealing of the alloy before oxidation increased the oxidation rate by a factor of {approximately}2.

• Sponsoring Organization: USDOE
• OSTI ID: 468390
• Journal Information: Oxidation of Metals, Journal Name: Oxidation of Metals Journal Issue: 1-2 Vol. 47; ISSN OXMEAF; ISSN 0030-770X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CHROMIUM ALLOYS
IRON BASE ALLOYS
OXIDATION
OXYGEN 18
TEMPERATURE RANGE 1000-4000 K
TRACER TECHNIQUES