Comparative investigation of surface modification and corrosion behaviour on SS304 and SS316 Coated with Inconel 625 in Air and Molten Salt Environment

Abstract

Abstract The high operating temperature-based industry extensively requires coating of material surfaces that are subjected to a high-temperature environment to improve their surface and resistance to corrosion. The current study investigated the surface modification and corrosion behaviour of Inconel 625 coated SS304 and SS316 materials in an air and molten salt environment at 800 °C. The plasma spray method was used to coat the Inconel 625 powder over the substrates. Techniques like quantitative weight gain/loss method, surface roughness, hardness measurement, and characterization through microstructure analysis were used to characterize and analyze the corrosion behaviour and microstructure of Inconel coated SS. It was observed that the coat had a noticeably layered structure with layers parallel to the surface of the substrate. The experimental results revealed that the uncoated SS suffered corrosion in the form of residue and peeling up of its oxide scale. Whereas the surface of the IN625 coated SS showed excellent resistance to corrosion formation. It was found that the coating lowered the mass gain of the SS316 by 65% when compared to uncoated SS.