Development and corrosion behavior of electrodeposited FeCoNiMoW and FeCoNiMoWCr high entropy alloy coatings

This study aims to develop FeCoNiMoW and FeCoNiMoWCr high entropy alloys (HEAs) coatings from the electrodeposition route using chloride-based aqueous electrolytes. The corrosion behavior of these electrodeposited coatings was investigated. The co-deposition of all five and six elements in HEA coatings was revealed by the energy dispersive X-ray spectroscopy (EDS) investigation. The scanning electron microscopy (SEM) analysis showed that the coatings had flaky-kind morphology with a mixing entropy of more than 1.5 R. The wettability test results showed that the surfaces of FeCoNiMoW and FeCoNiMoWCr HEA coatings were hydrophilic and hydrophobic, respectively. HEA coatings showed a higher corrosion resistance than the nickel aluminum bronze (NAB) alloy substrate. Both the HEA coatings have an anodic protection effect for the NAB substrate, providing a corrosion protection efficiency of up to 48.69 %. The Cr-containing FeCoNiMoW HEA coatings possess the best corrosion resistance . The corrosion current density of FeCoNiMoWCr HEA coating is 3.53 ± 0.72 µA/cm 2 . The Cr in the FeCoNiMoWCr HEA coating enhances the formation of metallic oxides film on its surface, which decreases the corrosive ion diffusion in the coating. • Electrodeposition of FeCoNiMoW and FeCoNiMoWCr HEA coatings from an aqueous medium. • The as-deposited HEA coatings exhibited a single-phase FCC solid solution. • A comprehensive study of the corrosion behavior and surface oxide chemistry of the electrodeposited HEA coatings. • The FeCoNiMoWCr HEA coating has better corrosion resistance than the FeCoNiMoW HEA coating.