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°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 NiCr 2 O 4 , NiAl 2 O 4 and Al 2 O 3 on the coated superalloys provided a higher hot corrosion resistance as observed in the present work.