High-temperature corrosion behavior of coatings and ODS alloys based on Fe{sub 3}Al

Conference · Thu Aug 01 04:00:00 EDT 1996

OSTI ID:458959

Tortorelli, P F; Pint, B A; Wright, I G ^[1]

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1. Oak Ridge National Lab., TN (United States)

Iron-aluminide coatings were prepared by gas tungsten arc and gas metal arc weld-overlay techniques. All the weld overlays showed good oxidation/sulfidation behavior under isothermal conditions, including a gas metal arc deposit with only 21 at.% Al. A rapid degradation in corrosion resistance was observed under thermal cycling conditions when the initially grown scales spalled and the subsequent rate of reaction was not controlled by the formation of slowly growing aluminum oxides. Higher starting aluminum concentrations (>{approximately}25 at.%) are needed to assure adequate oxidation/sulfidation lifetimes of the weld overlays. A variety of stable oxides was added to a base Fe-28 at.% Al-2 % Cr alloy to assess the effect of these dopants on the oxidation behavior at 1200{degrees}C. A Y{sub 2}O{sub 3} dispersion improved the scale adhesion relative to a Zr alloy addition, but wasn`t as effective as it is in other alumina-forming alloys. Preliminary data for powder-processed Fe-28 at.% Al-2% Cr exposed to the H{sub 2}S-H{sub 2}-H{sub 2}O-Ar gas at 800{degrees}C showed that the oxidation/sulfidation rate was similar to that of many Fe{sub 3}Al alloys produced by ingot metallurgy routes.

• Research Organization: Oak Ridge National Lab., TN (United States)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 458959
• Report Number(s): ORNL/FMP--96/1; CONF-9605167--; ON: DE97050349
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CHROMIUM ALLOYS
CORROSION RESISTANCE
IRON BASE ALLOYS
OXIDATION
PROTECTIVE COATINGS
SCALING
SULFIDATION
TEMPERATURE RANGE 1000-4000 K