Effect of Cl– and SO42– concentration in bicarbonate solutions on corrosion behavior of Cu
摘要
The effect of Cl– and SO42– on corrosion behavior of pure copper in simulated groundwater was investigated by electrochemical testing techniques, scanning electron microscope/energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction in 0.1 mol/L NaHCO3 solutions. The results indicate that increasing Cl– and SO42– reduces the corrosion resistance of Cu. Cl– and SO42– can promote anodic dissolution of Cu and deteriorate the passivation property. The breakdown potential (Eb) of Cu decreases with the increase in Cl– and SO42–. With the increase in immersion time, the polarization resistance in different solutions tends to be stable. After 55 days, polarization resistance (Rp) was almost equal in 0 and 0.01 mol/L Cl– and SO42– solutions. In 0.05 mol/L Cl– and SO42− solution, Rp was lower. HCO3– has a certain corrosion effect on Cu and the pits size increased with the increase in Cl– and SO42–. The corrosion products (Cu2(OH)2CO3) and CuO were detected in solutions without or at low Cl– and SO42– contents. The corrosion product after immersion in the solution containing 0.05 mol/L Cl– and SO42– was Cu2O.