Microstructure and electrochemical properties of FeNiCoCu medium entropy alloy-graphene oxide composite coatings

摘要

FeNiCoCu medium entropy alloy-graphene oxide (MEA-GO) composite coatings were electrodeposited on mild steel substrate and their microstructure and electrochemical properties were investigated as a function of the GO content. The FeNiCoCu MEA coating microstructure consisted of a mixture of Fe, Ni and Co containing body centered cubic (bcc) phase and highly Cu-rich dendritic face centred cubic (fcc) phase. With GO addition, the microstructure changed considerably to one containing highly Fe-rich bcc phase and fcc phase with Ni, Co and Cu elements. Fe-rich phase was present along with GO in the coating microstructure. The MEA coatings uniformity and grains compactness improved with increase in the GO content. Electrochemical properties of the coatings were investigated by open circuit potential (OCP), potentiody-namic polarization and electrochemical impedance spectroscopic (EIS) techniques. It was observed that the corrosion resistance of the MEA coatings increased with increase in their GO content. The enhancement in the corrosion resistance of MEA-GO composite coatings was attributed to the improved coating uniformity, grains compactness, impermeability of GO and formation of relatively stable protective Fe-oxide layer on the coating surface. (C) 2021 Elsevier B.V. All rights reserved.