Abstract
Hot corrosion and long-time dynamic oxidation tests were conducted on several alloy (equiaxed MM-0011 and IN738. SX CMSX-4. and DS CM186LC) and coating (Simple aluminide, Pt-aluminide, and NiCoCrAlY) combinations. The coating performance in both hot corrosion and oxidation testing was, in most cases, influenced by the substrate composition. An overlay NiCoCrAlY on either CMSX-4 or CM186LC appeared unaffected visually, but there were indications during metallographic examination that this coating substrate combination was beginning to degrade after a 1000 hour hot corrosion test. The results of the oxidation test indicated that several of the alloy/coating combinations that were superior in the hot corrosion test were inferior in oxidation. After 6000 hours of dynamic oxidation testing at 1038°C (1900°F) two of the alloy/coating combinations had not yet reached negative weight changes. Metallographic results from the oxidation test show a significant reaction layer in the CMSX-4 coated with either simple or modified aluminides or NiCoCrAlY overlay coatings.
Published Version
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