Corrosion behavior of as-sprayed VC-CuNiCr based coatings developed by high-velocity oxygen fuel process

Abstract

In this investigation, the high-velocity oxygen fuel (HVOF) deposition technique was implemented to administer vanadium carbide (VC) and cupronickel-chromium (CuNiCr) composite coatings onto SS316 stainless steel. The significance of this research lies in its direct relevance to addressing corrosion-related challenges in marine environments. Preceding and subsequent to the execution of electrochemical corrosion examinations within a 3.5% sodium chloride (NaCl) medium at ambient temperature, a comprehensive scrutiny of the surface topographies of both the coated and uncoated specimens was conducted through scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The outcomes manifest that the intermetallic binder composed of copper (Cu), nickel (Ni), and chromium (Cr) within the coatings undergoes deterioration under the influence of the NaCl medium, thereby inducing localized pitting corrosion phenomena across the substrate. Intriguingly, the incorporation of VC within the coating formulation conspicuously amplifies the corrosion resistance attributes of the treated surface, thereby ameliorating the occurrence of confined corrosive pits. Amidst the assortment of coatings subjected to scrutiny, the VC imbued surface attains the most favorable outcome, showcasing minimal corrosion rate of 72.38×10⁻³ mm/a. In contrast, the SS316 base substrate exhibits the most escalated corrosion rate calculated at 783.82×10⁻³ mm/a.