Corrosion behaviour of Cu-2Ti and Cu-2Zr (wt%) alloys in neutral aerated sodium chloride solution

The corrosion behaviour of Cu-2Ti and Cu-2Zr (wt%) alloys has been assessed by open-circuit potential and electrochemical impedance spectroscopy measurements carried out in 3.5 wt% NaCl solution, at approximately neutral pH, without stirring and in contact with the air. For comparison, the electrochemical tests have also been carried out on unalloyed Cu. Electrochemical impedance results showed that Ti and Zr alloying additions significantly increased the corrosion resistance of copper, the best behaviour being observed for the Cu-2Zr alloy. This improvement may be ascribed to the formation of Ti- or Zr-enriched passive layer, which exhibits higher protective effectiveness compared with that of unalloyed Cu.