Fe–Cr–Ni–Co–Cuxcoatings for marine and coastal infrastructure protection from corrosion, tribocorrosion and biofouling

Abstract

The aim of this study is to investigate the effect of varying copper (Cu) content on the structure, corrosion, tribocor-rosion, and bactericidal properties of FeCrNiCo-Cuxcoatings. Specifically, the main idea is to maximize the Cu content without secondary phases formation using Electrospark Deposition (ESD) method characterized by rapid cooling rates of the melt, while maintaining the corrosion properties of the Cu-free coating, and simultaneously en-hancing its antimicrobial and tribocorrosion properties. To achieve this, thick high-entropy Fe-Cr-Ni-Co-(Cu) coatings with different Cu content (up to 24 at. %) were obtained in a protective argon atmosphere. All coatings exhibited a single-phase structure based on a solid solution with an fcc lattice, dense and homogeneous microstruc-ture with high continuity. In tribocorrosion conditions, the FeCrNiCo coating demonstrated the lowest corrosion current, while the FeCrNiCo-12Cu coating revealed the most positive corrosion potential. However, after a certain Cu content threshold, tribocorrosion behavior deteriorated significantly. In terms of wear, coatings with high Cu content exhibited the highest wear resistance, which did not correlate with the hardness of the coatings. All coatings demonstrated a moderate antibacterial effect against B. cereus Arc30, with the FeCrNiCo-12Cu coating showing the highest ability to suppress bacterial growth and further biofilm formation.