Corrosion behavior of LY12CZ aluminum alloy in simulated acid rain solution

The variations of corrosion potential, electrochemical impedance and surface morphology of LY12 alumi-num alloy with pH of simulated acidic rain solutions were investigated with EIS and SEM. It is found that corrosionpotential shifts to less noble value with increasing pH in the solutions of pH lower than 3.1 and shifts to more noblevalue in the solutions of pH higher than 3.1. In the solutions of pH lower than 3.1,the electrochemical impedancediagram has a capacitive loop at higher frequency and an inductive loop at lower frequency and the magnitude of highfrequency loop decreases with decreasing pH and increasing period of immersion. However, in the solutions of pHhigher than 3.4 two capacitive loops appear and the magnitude of high frequency loops increases with pH and periodof immersion. Observation of SEM shows that the pitting intensity increases with decreasing pH in the range ofpH2.0～3.4, no evident pits are observed at pH higher than 3.4. The experiment results were discussed from re-sistance of oxide film and adsorption processes of anions in simulated acid rain solution.