Hot corrosion behaviour of D-gun sprayed NiCoCrAlYTa coated superalloys at 900°C in molten salt environment

Detonation-gun sprayed NiCoCrAlYTa coatings deposited on superalloys have been investigated for their hot corrosion behaviour at 900 degrees C in molten salt environment under cyclic conditions. The weight change measurements made on the bare and coated superalloys were used to determine the kinetics of hot corrosion. X-ray diffraction, X-ray mapping and field emission scanning electron microscope/EDS were used to characterise the corroded products of the coated and bare superalloys and substantiate the corrosion mechanisms. The formation of scales such as NiCr2O4, NiAl2O4 and Al2O3 on the coated superalloys provided a higher hot corrosion resistance as observed in the present work.