The corrosion of some superalloys in contact with coal chars in coal gasifier atmospheres
Six alloys, 310 stainless steel, Hastelloy X, Inconel 671, Incoloy 800, Haynes 188, and FeCrAlY (GE1541 and MA956), were corroded in two chars at 160/sup 0/C and 1800/sup 0/C. The chars, FMC and Husky, contained 2.7% and 0.9% sulfur, respectively. Various parameters were investigated, including char size, cover gas, char quantity, char replenishment period, gas composition, and the use of coatings. The corrosion process was strictly sulfidation when the char was replenished every 24 hr or less. The kinetics of reaction were nearly linear with time. The reaction resulted in thick external sulfide scales with extensive internal sulfidation in the substrate. The kinetics and reaction-product morphologies suggested that diffusion through the sulfide scale played a minor role, and that an interfacial reaction was the rate-controlling step. A mathematical model was developed which supported this hypothesis. The reaction rates showed a relatively minor role on alloy composition, depending upon whether the alloys were tested singularly or in combination with others. Inconel 671, the best alloy in CGA environments, consistently corroded the most rapidly of the chromia-former types regardless of char sulfur content or of the temperature. Type 310 stainless was marginally better than Inconel 671. Incoloy 800 was intermediate, wheras, Haynes 188 and Hastelloy X exhibited the best corrosion resistance. The FeCrAlY alloys reacted very rapidly in the absence of preoxidation treatments. All alloys corroded in char at least 1000 times more rapidly than in the CGA (MPC-ITTRI) environment. None of the alloys will be acceptable for use in contact with char unless coatings are applied.
- Research Organization:
- Materials Department, School of Engineering and Applied Science, University of California, Los Angeles, California.
- OSTI ID:
- 7096636
- Journal Information:
- Oxid. Met.; (United States), Journal Name: Oxid. Met.; (United States) Vol. 16:1/2; ISSN OXMEA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Corrosion of some superalloys in contact with coal chars in coal gasifier atmospheres
Mechanisms of corrosion of structural materials in contact with coal chars in coal gasifier atmospheres. Semi-annual progress report
Related Subjects
010404 -- Coal
Lignite
& Peat-- Gasification
36 MATERIALS SCIENCE
360105* -- Metals & Alloys-- Corrosion & Erosion
ALLOY SYSTEMS
ALLOYS
ALUMINIUM ADDITIONS
ALUMINIUM ALLOYS
ATMOSPHERES
CHARS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CHROMIUM STEELS
CHROMIUM-NICKEL STEELS
COAL GASIFICATION
COBALT ALLOYS
CORROSION
CORROSION RESISTANT ALLOYS
CORROSIVE EFFECTS
GASIFICATION
HASTELLOY X
HASTELLOYS
HAYNES 188 ALLOY
HEAT RESISTANT MATERIALS
HEAT RESISTING ALLOYS
INCOLOY 800H
INCOLOY ALLOYS
INCONEL 671
IRON ALLOYS
IRON BASE ALLOYS
KINETICS
MANGANESE ADDITIONS
MANGANESE ALLOYS
MATERIALS
MATHEMATICAL MODELS
MOLYBDENUM ALLOYS
NICKEL ALLOYS
NICKEL BASE ALLOYS
PYROLYSIS PRODUCTS
QUATERNARY ALLOY SYSTEMS
REACTION KINETICS
SILICON ADDITIONS
SILICON ALLOYS
STAINLESS STEEL-310
STAINLESS STEELS
STEELS
SULFIDATION
THERMOCHEMICAL PROCESSES
TITANIUM ADDITIONS
TITANIUM ALLOYS
TUNGSTEN ALLOYS
VERY HIGH TEMPERATURE
YTTRIUM ALLOYS