ELECHTROCHEMICAL BEHAVIOR AND CORROSION RESISTANCE OPTIMIZATION OF ELECTRODEPOSITED CU/WC NANOCOMPOSITE BY DOE1 METHOD

In this investigation electrodeposition of WC nanoparticles in a copper metal matrix from copper sulphate bath was obtained and characterized. Temperature and stirring rate of the bath were initially studied and optimized to obtaining minimum corrosion current density. The corrosion resistance of composite coatings is optimized by design of experiment (DOE) method (Central Composite Design) using DC electrodeposition. Current density and concentration of WCand SDS were selected as the most important system variables. 15 experiments were designed bythe CCD method. From results of these 15 experiments obtained from Analyses of Variance (ANOVA), the best model which predicted the corrosion behaviour of Cu/WC composite were found and introduced. Quadratic behaviour of WC nanoparticles and linear behaviour of SDS andcurrent density were found as the most significant terms in corrosion resistance of Cu/WC composites which obtained from ANOVA model. Serious interaction of current density with WC and SDS content were also found in this model. Finally the optimum conditions of WC, SDS andcurrent density for obtaining coatings with lowest corrosion current density (1.67*10-5) were discovered. The potentiodynamic polarization behavior of Cu/WC coating samples was compared with that of pure Cu in freely aerated 1% NaCl solutions. Cu/WC composite which is electrodeposited with 2.32 A/dm2 current density, 25.9 g/lit WC and 0.034 g/l SDS in 40ºC bath temperature, 600 rpm stirring rate and pH 1 were assessed as the optimum conditions to obtaining lower corrosion current density.