An investigation on anti-corrosion properties of electroplated copper graphene nano-composites

Abstract

In this report, graphene sheets have been synthesized by electrochemical intercalation and exfoliation process. The (001) and (002) plane of graphene sheets at a 2θ angle of 13.2 and 26.13 confirmed by X-ray diffraction pattern. (001) plane shows graphene oxide present in prepared graphene sheets. Transparent like layer confirmed from transmission electron microscope (TEM). High-resolution TEM confirms 8-12 layers present in graphene sheets. The as-received graphene sheets have been used as reinforcement with copper matrix to synthesize Cu-Gr nanocomposite by electrodeposition method. The results and investigations of Cu-Gr composite thin films deposited from the bath containing 0.1g/L and 0.5g/L graphene concentrations with acidic copper sulfate solution have been compared. The surface morphology and roughness of composites were studied by SEM, AFM and surface profiler. The presence of graphene in Cu-Gr nanocomposite confirmed by EDS analysis. It was observed that the reinforcement particle has increased the mechanical properties of Cu-Gr composite with the addition of copper matrix. The hardness of 0.5g/L Cu-Gr composite shows 30% higher hardness as compared to copper thin film. The corrosion resistance of sample was studied by a voltammetric method in standard borate buffer solution. The corrosion properties like Tafel constants and corrosion potential and currents were extracted and analyzed. For nano-composites of 0.5g/L graphene % the values are, βa=177.37 mv, βc=138.51 mv, Icorr = 9.3165×10-7Amp/cm2, Ecorr = -0.051 volts and corrosion rate 0.01028 mm/a as comparison to the corrosion rate of pure electroplated copper of a value of 0.029 mm/a. The corrosion rate of 0.5g/L Cu-Gr composite was found to be decreased by 2.7 times as compared to pure copper thin films. The structure of the films before and after corrosion was also analyzed to co-relate the electrochemical and structural relationship.