Study Of The Hot Corrosion Of Superalloys
Report Number: AFML TR 67-297
Author(s): Walters, J. J.
Corporate Author(s): Avco Lycoming Div Stratford CT
Laboratory: Air Force Materials Laboratory
Date of Publication: 1967-09
Pages: 159
DoD Task:
Identifier: AD0822779
Abstract:
The effect of operating environment and alloy composition on the nature and extent of oxidation-sulfidation attack was studied with the aid of the Lycoming environmental test rig, which operates at one atmosphere pressure. Sulfidation attack was produced by burning JP-4, JP-4R, and JP-5 fuels (sulfur contents of .02, .16, and .16 weight percent respectively) while ingesting synthetic sea water at controlled rates to yield salt/air ratios of 4ppm and 8ppm. Specimens of 11 nickel base and one cobalt base alloy were subjected to cyclic temperatures, holding at peak temperatures of 1600 F or 1750 F for ten minutes per cycle. The temperature range over which sulfidation occurred and the depth of attack increased with increasing salt-to-air ratios and with time of exposure. Good resistance to attack was generally associated with higher chromium content but high chromium alone did not guarantee good resistance to attack. Microprobe and x-ray investigations indicated that chromium-rich surface oxides provide good resistance to sulfidation and that high aluminum-titanium ratios provide good oxidation resistance.
Provenance: Lockheed Martin Missiles & Fire Control
Author(s): Walters, J. J.
Corporate Author(s): Avco Lycoming Div Stratford CT
Laboratory: Air Force Materials Laboratory
Date of Publication: 1967-09
Pages: 159
DoD Task:
Identifier: AD0822779
Abstract:
The effect of operating environment and alloy composition on the nature and extent of oxidation-sulfidation attack was studied with the aid of the Lycoming environmental test rig, which operates at one atmosphere pressure. Sulfidation attack was produced by burning JP-4, JP-4R, and JP-5 fuels (sulfur contents of .02, .16, and .16 weight percent respectively) while ingesting synthetic sea water at controlled rates to yield salt/air ratios of 4ppm and 8ppm. Specimens of 11 nickel base and one cobalt base alloy were subjected to cyclic temperatures, holding at peak temperatures of 1600 F or 1750 F for ten minutes per cycle. The temperature range over which sulfidation occurred and the depth of attack increased with increasing salt-to-air ratios and with time of exposure. Good resistance to attack was generally associated with higher chromium content but high chromium alone did not guarantee good resistance to attack. Microprobe and x-ray investigations indicated that chromium-rich surface oxides provide good resistance to sulfidation and that high aluminum-titanium ratios provide good oxidation resistance.
Provenance: Lockheed Martin Missiles & Fire Control