Effect of preoxidation on the corrosion of some superalloys in coal char
Preoxidation of several chromia-forming and of several alumina-forming alloys at temperatures ranging from 982 to 1260/degree/C in either water-saturated argon or in air was performed prior to corrosion in coal char. Chromia films offered no protection to subsequent sulfidation in char. The chromia films were adherent but permitted rapid inward penetration of sulfur and outward penetration of cations to form extensive sulfides. Alumina films offered protection for much longer times than did chromia films, but localized cracking and/or spalling of the alumina permitted rapid attach at the exposed areas. The addition of yttrium as either a metallic element or an an oxide dispersion improved the mechanical stability of the films and prolonged the period of protectiveness. Alumina films would provide an excellent protective barrier, if thick crack-free films could be grown at reasonable temperatures. The low growth rates at very high temperatures and the susceptibility of alumina films to crack and spall during thermal cycling suggest that preoxidation will not offer adequate corrosion resistance for alloys exposed to char in goal gasifiers.
- Research Organization:
- Scanning Electron Analysis Labs., Los Angeles, CA (USA)
- OSTI ID:
- 6094948
- Journal Information:
- Oxid. Met.; (United States), Journal Name: Oxid. Met.; (United States) Vol. 29:3-4; ISSN OXMEA
- Country of Publication:
- United States
- Language:
- English
Similar Records
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Related Subjects
010404 -- Coal
Lignite
& Peat-- Gasification
36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOY-CO36CR22NI22MO15FE3
ALLOY-NI49CR22FE18MO9
ALLOY-NI51CR48
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AUSTENITIC STEELS
CHALCOGENIDES
CHARS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CHROMIUM COMPOUNDS
CHROMIUM OXIDES
CHROMIUM-NICKEL STEELS
COAL GASIFICATION PLANTS
COATINGS
COBALT ALLOYS
COBALT BASE ALLOYS
CORROSION PROTECTION
CORROSION RESISTANCE
CORROSION RESISTANT ALLOYS
CORROSIVE EFFECTS
CRYSTAL STRUCTURE
ELEMENTS
HASTELLOY X
HASTELLOYS
HAYNES 188 ALLOY
HAYNES ALLOYS
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
HIGH ALLOY STEELS
INCOLOY 800
INCONEL 671
INDUSTRIAL PLANTS
IRON ALLOYS
IRON BASE ALLOYS
LANTHANUM ADDITIONS
LANTHANUM ALLOYS
MATERIALS
METALLURGICAL EFFECTS
METALS
MICROSTRUCTURE
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NICKEL BASE ALLOYS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PROTECTIVE COATINGS
PYROLYSIS PRODUCTS
RARE EARTH ADDITIONS
RARE EARTH ALLOYS
SCALING
STAINLESS STEEL-310
STAINLESS STEELS
STEEL-CR25NI20
STEELS
TEMPERATURE EFFECTS
THERMAL CYCLING
TITANIUM ADDITIONS
TITANIUM ALLOYS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN ADDITIONS
TUNGSTEN ALLOYS
YTTRIUM