Hot Corrosion Studies on Detonation-Gun-Sprayed NiCrAlY and 80Ni–20Cr Coatings on Alloy X22CrMoV12-1 at 600 °C

Abstract

The present study investigates the type II low-temperature (600 °C) corrosion behavior of X22CrMoV12-1 substrate coated with NiCrAlY and 80Ni–20Cr powders through a detonation spray technique. Coated substrates and uncoated substrates were exposed to low-temperature corrosion test in both air oxidation environment and molten salt environment for 50 cycles at 600 °C. From the thermogravimetric analysis, it was seen that all the substrates trailed parabolic rate law. Higher weight gain resulted in the uncoated substrate under molten salt environment. NiCrAlY substrate showed lesser weight gain under air oxidation environment. It was also noted that lesser weight gain was observed in coated substrates (NiCrAlY and 80Ni20Cr) compared to the uncoated substrates. The presence of MnCr2O4, Ni3Al, NiO, Cr2O3, and Al2O3 provided good hot corrosion resistance to coated substrates. Thus, it showed that NiCrAlY and 80Ni–20Cr coated X22CrMoV12-1 substrate delivered adequate resistance to corrosion at 600 °C.