Hot corrosion behaviour of nickel-iron-based superalloy in gas turbine application

Nickel-based superalloys are mostly used as gas turbine components. During combustion, the sodium sulphate and sodium chlorides with vanadium pentoxide are dominating corrosive species in gas turbine environment. The eutectic point of the salt deposits varies with respect to combustion/operating temperature and corrosion kinetics are initiated. In this research, hastelloy X was chosen as a candidate material in a simulated oxidation and gas turbine hot corrosion at 1100 degrees C. The mass change per unit area is gradual in mixed salt environment and catastrophic under atmospheric air for oxidation studies. This observation may be due to the oxide scale formation and spalling of the same on prolonged exposure. The exposed samples were subject to SEM, EDS and XRD analysis. The samples exposed to molten salt have undergone different surface morphology during the incubation period. The features of the candidate material are discussed in detail.