Cyclic voltammetric studies carried out on copper, nickel and 70/30 cupronickel in 0.5 M NaCl solutions revealed that the I passivation of copper is due to the formation of Cu2O via CuCl2- and that of nickel is due to oxide formation. X-ray diffraction (XRD) and X-ray photoelectron spectral (XPS) studies on cupronickel revealed the presence of partially covered surface with a corrosion film containing essentially Cu2O. Increase of anodic potential resulted in the formation of chloro hydroxy cupric compounds along with nickel oxide. At potential closer to oxygen evolution, divalent and trivalent oxides of nickel species were predominant. The surface film analysis by X-ray fluorescence (XRF) studies revealed the film to contain more copper than nickel at potential below + 200 mV (SCE). However, at higher anodic potentials the amount of nickel exceeded that of copper. The leaching of cupronickel alloy was found to be uniform and not a preferential one for a less noble metal, such as copper.