Influence of Cl⁻ Concentration on Corrosion Performance of Cu-Al Layered Composite Plate

The corrosion performance of the Cu-Al layered composite plates in a salt spray circumstance with different concentrations of NaCl solution was studied, and the relevant corrosion kinetic mode was established. In conjunction with the EIS (electrochemical impedance spectroscopy) and LSV (polarization curve tests), the effects of corrosion product films on the corrosion resistance of Cu-Al layered composite plates were investigated. The results show that the corrosion performance first evolved from pitting corrosion to crevice corrosion at the Cu-Al interface, and finally formed general corrosion on the aluminum matrix. The corrosion kinetics model roughly followed the power function law, the resistance to corrosion of the specimens was reduced as the growth of the concentration. Through the samples corroded for the short time (24 h) in the salt spray concentration of 5%, continuous and dense corrosion products were formed. The corrosion products could protect the matrix to delay the occurrence of corrosion in certain degree and be unable to alter trend of corrosion.