Hot corrosion behavior of NiCoCrAlYTa coating deposited on Inconel alloy substrate by high velocity oxy-fuel spraying upon exposure to molten V2O5-containing salts

The corrosion behavior of the HVOF-sprayed NiCoCrAlYTa coating upon exposure to molten V2O5 and molten mixture of 50 wt.% V2O5 + 50 wt.% Na2SO4 at 800-1000 °C was discussed. The hardness, elastic modulus and contact stiffness of the coating were determined by nano-indentation test. Results indicate that the coating exhibits good corrosion resistance, which is ascribed to the formation of Al and Cr oxide protective film. The generation of hard phases Al2O3 and Cr2O3 with loose structure and Laves phase Cr2Ta lead to the increase of the hardness and elastic modulus of the corroded coatings and the decrease of contact stiffness.