On the oxidation mechanism of alumina formers
- Technische Univ. Clausthal, Clausthal-Zellerfeld (West Germany)
The oxidation mechanism of the intermetallic compound {beta}-NiAl and Fe-23 Cr5Al-0.2 Zr alloys modified by reactive-element additions was studied in the temperature range 1,273-1,473 K by means of the two-stage oxidation method using the oxygen isotope {sup 18}O as a tracer. It was found that outward cation diffusion predominates in the scale on {beta}-NiAl. The contribution of the inward oxygen transport increased with increased reaction temperature and oxidation time. At 1,473 K, implanted yttrium suppressed inward oxygen diffusion for oxidation times less than 1 hr. In the case of Fe-Cr-Al-Zr alloys the counter-current transport of reactants was observed on the non-implanted materials. Implanted yttrium was found to alter the transport mechanism. This effect appeared to be directly related to that of yttrium on the scale morphology and microstructure, Yttrium promoted the formation of cracks which provided an additional surface for the reaction.
- OSTI ID:
- 5404087
- Journal Information:
- Oxidation of Metals; (United States), Journal Name: Oxidation of Metals; (United States) Vol. 36:3-4; ISSN 0030-770X; ISSN OXMEA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
COATINGS
CRACK PROPAGATION
CRYSTAL STRUCTURE
DATA
DIFFUSION
ELECTRON MICROSCOPY
ELEMENTS
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
INFORMATION
INTERMETALLIC COMPOUNDS
ION IMPLANTATION
IRON ALLOYS
IRON BASE ALLOYS
ISOTOPES
KINETICS
LIGHT NUCLEI
METALS
MICROSCOPY
MICROSTRUCTURE
MORPHOLOGY
NICKEL COMPOUNDS
NUCLEI
NUMERICAL DATA
OXIDATION
OXIDES
OXYGEN 18
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PROTECTIVE COATINGS
REACTION KINETICS
SCALING
SCANNING ELECTRON MICROSCOPY
STABLE ISOTOPES
TEMPERATURE RANGE
TEMPERATURE RANGE 1000-4000 K
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
YTTRIUM
ZIRCONIUM ADDITIONS
ZIRCONIUM ALLOYS