Effect of alloying elements on the electrochemical behavior of Cu-Ni-Zn ternary system in sulfide-polluted saltwater

Abstract Copper-based alloys suffer from accelerated corrosion in sulfide-polluted seawater. Herein, we investigated the effect of Ni and Zn as alloying elements on the electrochemical behavior of Cu in sulfide-polluted saltwater. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) measurements have been performed to assess the effect of Ni and Zn. The Cu–Ni–Zn alloy showed the lowest corrosion current density ( i corr ) in the highest concentration of sulfide-polluted saltwater compared to the Cu, Cu–Ni and Cu–Zn counterparts. Morphological (SEM) and surface (XPS) analyses have been done to further understand the findings of electrochemical measurements. Thin films of mixed oxides (CuO and ZnO) and hydroxides (Cu(OH) 2 , Ni(OH) 2 and (Cu, Zn) 2 (OH) 3 Cl) were identified as the reason behind the observed resistivity of the ternary Cu–Ni–Zn alloy.