Corrosion behavior of Cu/Al casting-rolled clad plates in different alkaline solution
Yifan Zhang, Xiaoguang Yuan, Xiaojiao Zuo, Hongjun Huang, Yulin Cheng
Abstract
The effect of pH value and different kinds of anions on the corrosion behavior of Cu/Al casting-rolled clad plates in the alkaline solution was evaluated by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), weight loss analysis, 3D confocal laser scanning microscopy (CLSM) and electrochemical test. Results show the corrosion mainly occurs on the aluminum side. The corrosion resistance of the Cu/Al decreases as the pH value increases. When pH≥12, the dissolution of the film layer is faster than the passivation process. The addition of Cl − ions reduces the corrosion resistance of the Cu/Al clad plates, which leads to pitting corrosion. The higher the concentration of Cl − ions, the more prone the pitting to occur. The addition of SO 4 2− ions causes the denudation of the samples. The corrosion resistance of the Cu/Al is better in the alkaline solution containing NO 3 − ions than that in the solution containing Cl − ions or SO 4 2− ions. When adding SO 4 2− , NO 3 − and Cl − to the pure alkaline solution, the corrosion resistance of the Cu/Al clad plates decreases.