Phase composition, surface chemistry and electrochemical studies of electrodeposited AlMnFeCuNi high entropy alloy composite coatings incorporated with carbon nanotubes

Abstract

AlMnFeCuNi high entropy alloy (HEA) coatings were electrodeposited onto mild steel substrate with and without incorporation of carbon nano tubes (CNT). This paper focused on the morphology, hardness, wear and corrosion behaviour for as deposited HEA and HEA-CNT coatings. Both the coatings constituted simple solid solution with face-centered cubic (FCC) structure. The addition of carbon nano tubes in the HEA coatings as revealed by scanning electron microscopy showed more smaller granules and compact morphology with least coating thickness value (5 ± 0.35 μm). Enhanced Anti-wear performance results in higher hardness and lower coefficient of friction. The presence of CNTs resulted improvised corrosion resistant properties in 3.5% NaCl corrosive media. The formation of more protective oxides such as Alox+3, Mnox+2 and Feox+3 on passive oxide layer in HEA-CNT coatings acted as a barrier, protected it from corrosion.