Hot corrosion resistance of a NiCrMoAlSi cladding layers under K2SO4-ZnCl2 molten salt film in air

This study aims to evaluate the hot corrosion resistance of a novel NiCrMoAlSi cladding layer compared to conventional Inconel 625 under a K2SO4–55 at.% ZnCl2 salt film at 650 °C and 700 °C, elucidating the role of Al and Si in enhancing protective oxide scale formation. Inconel 625 and NiCrMoAlSi cladding layers were prepared via laser cladding and subjected to 100-hour hot corrosion tests under a deposited salt film. Mass loss measurements, XRD, and SEM-EDS were employed to analyze corrosion products, scale morphology, and elemental distribution. The NiCrMoAlSi cladding layer exhibited significantly lower mass loss (2.63–6.43 mg/cm2) than Inconel 625 (27.05–27.52 mg/cm2), due to a dense, multi-layered oxide scale enriched with Cr and Al externally and Si internally. In contrast, Inconel 625 formed porous oxides and a Cr/Fe dissolution zone, leading to severe corrosion degradation.