The Effect of Current Density on Surface Properties of Electrodeposited Copper Coatings on Modified Aluminium

This study was done to investigate the effect of current density on the surface properties of copper (Cu) coatings on modified aluminium (Al) surface by electrodeposition technique. Cyclic voltammetry (CV) was performed to study the electrochemical behaviour of the modified Al (Ni-zincated Al) in an electrolyte solution of 0.1 M CuSO4 containing glutamate as complexing agent. Three different current densities (i.e.: -0.5, -3.0 and -6.0 mA/cm(2)) were chosen from CV for deposition of Cu using chronopotentiometric (CP) analysis. The Cu coatings were characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDAX) and X-ray diffraction (XRD) based on their morphology, elemental composition and crystallographic phase contents, respectively. The adhesion strength of copper coatings was analysed by Scotch (R) tape test. At lower current density, 0.5 mA/cm(2), a coating formed was discontinued with island-like structure as imaged by FESEM. Meanwhile, deposition using -3.0 mA/cm(2) produced continuous and compact coating with grains nodules crystalline structures. However, deposition at high current density -6.0 mA/cm(2), formed uneven copper nodules growing perpendicular to the Ni-zincated Al surface. The XRD analysis revealed that all copper coatings were composed of cubic crystalline structure. Meanwhile, EDAX analysis showed that Cu coating deposited at -3.0 mA/cm(2) has the highest copper content with 94.07 wt% and this coating condition was the most adhered coating. Thus, it can be concluded that current density has significantly affected the formation of Cu coatings on the modified Al surface.