Construction of NiCo/graphene nanocomposite coating with bulges-like morphology for enhanced mechanical properties and corrosion resistance performance

•Electrodeposited NiCo/rGO nanocomposite coatings have successfully constructed.•The effect of rGO nanoplatelets increase the microhardness of the NiCo metal matrix composite coatings.•The impact of rGO nanoplatelets cause the unique sphere-like morphology and grain refinement.•NiCo/rGO coatings can effectively enhance the corrosion resistance of Q235 steel. [Display omitted] Coatings with good mechanical, wear, erosion and corrosion protection properties are needed to protect the structural metals such as steels, which are enormously used in several engineering applications. For this purpose, NiCo and NiCo/rGO coatings are constructed onto the Q235 carbon steel through an electrochemical co-deposition process. The outcomes of this study deliver good mechanical properties and show better corrosion resistance against a corrosive environment. The incorporation of rGO nanoplatelets enable good mechanical and reinforcing properties as well as assist in the growth of unique sphere-like morphology with a higher microhardness of 590 HV and enhanced corrosion resistance 17.5 Rct/k Ωcm2 as compared to NiCo containing 325 HV and 4.55 Rct/k Ωcm2, respectively. In addition, the remarkable grain refinement is observed owing to the reinforcement of rGO platelets that support the formation of a large number of grain boundaries with less crystal growth and provide surface roughness as well as the cavities or pores are also filled by rGO platelets, which eventually contribute in enhancing the mechanical and corrosion properties of the steel substrate.