Hot corrosion studies of a salt-coated Ni-based superalloy under flowing wet air and sulfur vapor ambient

Corrosion of a salt-coated Ni-superalloy has been studied at 900 degrees C under a wet air and sulfur vapor ambient. The corrosion thickness, after an incubation of similar to 60 hr, linearly increases with the corrosion timetand the onset of surface spallation occurred att approximate to 60 hr. The corroded layer consists of a corrosion front dominated by Cr(3)S(4)scales and linear precipitate structures, an inner corrosion layer dominated by Ni(3)S(2)and NiO, and an outer corrosion layer dominated by Al(2)O(3)networks surrounding the Ni(3)S(2)and/or NiO scale structures. The corrosion mechanism is discussed based on the coexistence of H2O, sulfur, and oxygen.