Electrochemical Corrosion Behaviour of Microarc Oxidized Film on 2A12 Aluminium Alloy

The surface of 2A12 aluminium alloy fabricated by powder metallurgy has been modified by microarc oxidation. The microstructure and phase composition of the modified layer have been characterized, and the electrochemical corrosion performance of 2A12 aluminium alloy after surface modification has been evaluated. It is found that a uniform oxidized film with the depth of about 80 μm is formed on 2A12 aluminium alloy, which consists of α-Al₂O₃, γ-Al₂O₃ and amorphous structure. After surface modification by microarc oxidation, the modified layer on 2A12 aluminium alloy greatly inhibits the anodic and cathodic reactions of the alloy surface, and the corrosion current density and corrosion rate significantly decrease, suggesting the electrochemical corrosion performance of the alloy is obviously improved.