Microstructure-corrosion property correlation in electrodeposited AlCrFeCoNiCu high entropy alloys-graphene oxide composite coatings

AlCrFeCoNiCu high entropy alloys (HEA) composite coating with and without graphene oxide (GO) were electrodeposited over mild steel substrate. Potentiodynamic polarization and electrochemical impedance spectroscopy tests performed in 3.5 wt% NaCl aqueous solution showed that the corrosion resistance of the HEA-GO composite coatings was higher than the HEA coating without GO. The corrosion resistance gradually increased with increase in the GO amount in the coating. Detailed microstructural characterization performed using transmission electron microscopy technique revealed that addition of GO facilitated microstructural and compositional homogeneity which eliminated localized corrosive attack due to elemental segregation induced galvanic coupling thereby increasing the corrosion resistance for the HEA-GO composite coatings.