Artículos de revistas
Anodically grown films on copper and copper-nickel alloys in slightly alkaline solutions
Brizuela, F.; Procaccini, Raul Ariel; Ceré, Silvia; Vazquez, Marcela Vivian; Anodically grown films on copper and copper-nickel alloys in slightly alkaline solutions; Springer; Journal of Applied Electrochemistry; 36; 5; 1-2-2006; 583-590
Procaccini, Raul Ariel
Vazquez, Marcela Vivian
Surface oxides grown on copper and copper–nickel alloys (UNS 72000 and UNS 70600) in aerated borax-borate buffer solution of pH 7.7 were characterized using various experimental techniques. Their influence on the mechanism of oxygen reduction was also investigated. The composition of the passive films formed in situ on the different materials was studied using differential reflectance spectroscopy. Electrochemical techniques such as voltammetry and potentiodynamic reductions, as well as hydrodynamic tools such as the rotating disk electrode were used to characterize the kinetic parameters of the oxygen reduction reaction. The results show that the addition of Ni to Cu to form copper–nickel alloys changes the composition of the surface film. As the amount of Ni in the alloy increases, the proportion of Cu(I) compounds decreases, and Ni(II) compounds are incorporated into the film structure. The films anodically grown at 0.5 V on Cu70Ni30 tend to be thinner but more resistive. This is supported by results from reflectance and impedance spectroscopy. The kinetics of oxygen reduction follows a four-electron path on surfacefree films, independently of the Ni-content in the alloy.