Sealing of ammonium adipate on anodic oxide film of aluminium alloy 2024-T3 under voltage loading

In order to put forward a new sealing method, the sealing effect of ammonium adipate on anodic oxide films of aluminium alloy 2024-T3 under voltage loading is studied. The surface morphology and element contents of the anodic oxide films before and after the sealing are studied by using the field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and salt spray tests are used to study the corrosion resistance of the anodic oxide films sealed by different methods. It is shown that, after the ammonium adipate sealing under voltage loading, the pores of the anodic oxide films are closed, the cavities of the anodic oxide films are filled, the defects of the barrier layer are repaired, and the thickness of the barrier layer is enhanced. The corrosion resistance of the films sealed by ammonium adipate under voltage loading is comparable to those sealed by potassium dichromate, and superior to the films sealed by boiling water.