Investigation into the Corrosion Behavior of Copper/Aluminum Associated with Electric/Electronic Devices in Marine Environment

Corrosion behavior of copper/aluminum was investigated using cyclic wet/dry corrosion test in natural seawater by electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM). The higher charge transfer resistance ( R ct ) and film resistance ( R f ) at 15 d of w/d cyclic corrosion test were shown by EIS plots. The anodic surface releases Al 3+ and Cu + ions into the electrolyte, and the cathodic surface consumes dissolved oxygen. These ions and dissolved oxygen are detected by applying appropriate tip potential in SECM technique. The results showed that the corrosion activity of aluminum was accelerated due to the potential difference of the sample. The scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX) analysis showed the enrichment of Cu and Al in corrosion products at the surface of Cu/Al sample after electrochemical analysis. The focused ion beam/transmission electron microscopy (FIB-TEM) analysis confirmed the presence of the nanoscale oxide layers containing Cu and Al in the corrosion product of the Cu/Al sample. The formation of corrosion products has a beneficial effect on corrosion resistance of Cu/Al sample.