The effect of Graphene content on the corrosion and mechanical properties of an electrodeposited Ni-Graphene coating

Abstract

Ni-Graphene coatings were developed on a mild steel substrate by electrodeposition from an electrolyte solution of nickel sulphate. Graphene was utilised in the electrolyte at volume fractions of 0.25, 0.5, 0.75, and 1 g/l.The low volume proportion of graphene can boost ion and electron mobility, promote cathodic polarisation potential, and accelerate the formation of heterogeneous microstructure features.The electrochemical route was employed to investigate the influence of graphene content on the corrosion behaviour of electrodeposited coatings. The coating structure and surface morphology were measured using X-ray diffraction and scanning electron microscopy. Microhardness test, scratch test, AFM imaging and profilometry were conducted to study the mechanical characteristics of the coating. The corrosion rate dropped from 3.624 mil/year for the nickel sample to 1.891 mil/year for the Ni-Graphene sample with 1 g/l graphene concentration. For the Ni-Graphene coatings, a surface morphology resembling a bulged flake was observed in the SEM. The uniform distribution of graphene with improved roughness was achieved in the coating. The substrate and the adjacent layers were not affected by the scratch test.