No abstract

3 at temperatures higher than 600°C were evaluated using an open-circuit potential followed by a potentiodynamic polarization sweep to determine the corrosion rates. Because the best-performing alloys at 750°C were In800H followed by SS310, these two alloys were selected as the substrate material for the MCrAlX coatings. The coatings were able to mitigate corrosion in molten carbonates environments. The corrosion of substrates SS310 and In800H was reduced from ~2,500 µm/year to 34 µm/year when coated with high-velocity oxyfuel (HVOF) NiCoCrAlHfSiY and pre-oxidized (air, 900°C, 24 h, 0.5°C/min) before molten carbonate exposure at 700°C in bone-dry CO 2 atmosphere. Metallographic characterization of the corroded surfaces showed that the formation of a uniform alumina scale during the pre-oxidation seems to protect the alloy from the molten carbonate attack.