Comparative corrosion studies of composite coating by impedance spectroscopy method. 2 - Comparative corrosion study of copper and copper zirconia composite coatings in sulphuric acid solutions

This paper investigates the corrosion behaviour of copper and copper-matrix composite coatings, with zirconium oxide particles embedded during electro deposition from an acid copper sulphate-plating bath. The corrosion studies were carried out on the basis of the polarisation resistance measurements by means of the impedance diagrams plotted in the complex plane, and Farada ic distortion method in the following aerated solutions: 0.5 M H2SO4, 1 M H Cl. The results are discussed by taking into account the possible influence of disperse phase in the mechanism of electrodeposited copper corrosion. T he zirconium oxide particles embedded in the electroplated copper increase the polarisation resistance and:decrease three times the corrosion rates in sulphuric acid as compared with electrodeposited pure copper. The results of the corrosion rate measurements performed by electrochemical impedance a nd Faradaic distortion methods were in a good agreement. The increase of pH enhances the corrosion protective effect of zirconium oxide particles in c omposite coating in the chloride solution.