Corrosion inhibition behavior of cerium salt sealing on the scratch of aluminum alloy anode oxide film in a simulated marine atmospheric environment

Abstract

The anodic oxide film of aluminum alloy was sealed by cerium salt, and the scratch test was used to simulate the damage of the oxide film. The repair and corrosion inhibition effects of cerium in the oxide film on the simulated damaged site were studied by means of alternate immersion accelerated corrosion test, combined with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. The results show that cerium in the undamaged oxide film diffused to the scratch and existed in the form of Ce (III) and Ce (IV), and formed the hydroxide with the cathode reaction product OH− in the scratch. It was only when enough corrosion products were produced on the aluminum matrix in the scratch, both the corrosion products and the hydroxide of cerium would have a synergistic effect on inhibiting the cathode reaction, thus, cerium salt could play the role of corrosion inhibition.