Salt induced corrosion behaviour of superalloy IN718

Nickel-ferrous based superalloy IN718 is used in gas turbine engine as compressor disk and blade. The performance of these components is severely affected in marine environment. This investigation deals with NaCl salt induced corrosion of the superalloy IN718 at 600°C. NaCl was deposited on the sample using spray gun technique. The uncoated and NaCl coated samples were exposed in air at 600°C under cyclic heating and cooling for 100hrs. Various characterization techniques such as XRD, SEM and EDS were used to identify the oxidation and corrosion products. It was observed from the XRD and SEM/EDS analysis that the uncoated sample did not oxidize at 600°C, however, the NaCl coated sample was heavily corroded and various complex oxides were observed on the sample. Weight gain/loss measurements were made to determine the corrosion kinetics. The coating of NaCl was found to be highly detrimental for corrosion resistance of this alloy.