2011 Volume 60 Issue 1 Pages 22-27
In this work, polarization measurement, galvanic current density measurement and spray test were carried out on aluminum (Al), copper (Cu) and Al/Cu couples in NaCl aqueous solutions with different temperatures and different levels of NaCl and aeration. The corrosion current density of Al at 323 K in aerated 1.0 mass% NaCl solution is about 60 times as high as that deaerated with nitrogen, whereas the corrosion current density in aerated 1.0% NaCl solution at 323 K is about 3 times as high as that at 303 K. The corrosion potentials of Al and Cu shifted to negative direction when the NaCl concentration increased from 0.01% to 1.0%. A clear passive region was observed on the Al specimen when the NaCl concentration is below 0.005%. The galvanic current density between the Al/Cu couple increased with the increase in NaCl concentration. In the spray test, the corrosion on the Al side of the Al/Cu couple became more severe with the increase in NaCl concentration and the decrease in the face-to-face distance between Al and Cu.