Salt spray corrosion and electrochemical corrosion property of anodic oxide films on ADC12 aluminum alloy

Abstract

Anodic oxide films were prepared by anodic oxidation on the surface of ADC12 aluminum alloy and their corrosion properties were explored. The original samples, anodized samples, and sealed samples were placed in the salt spray corrosion chamber and were taken out at different times. Then the corrosion resistance of the ADC12 aluminum alloy was discussed, and the electrochemical corrosion test was researched. The results indicated that the surface of the original samples reveals many large-area pits after salt spray corrosion, while the sealed samples present a smoother surface. The dense oxide films on the surface of the base metals effectively prevent Cl[Formula: see text] entering into aluminum alloys especially after sealing. Electrochemical tests including the potential polarization curve and electrochemical impedance spectroscopy (EIS) as functions of exposure time were employed to reveal the corrosion behavior of surface layers. After the sealing treatment on the oxide films, the corrosion potential moved in the positive direction, the corrosion current density decreased, and the corrosion resistance of the ADC12 aluminum alloy was significantly improved.