Preparation and Properties of Hydrophilic Film on Aluminum Alloy Surface

In order to enhance the hydrophilicity and corrosion resistance of aluminum alloy surface， a hydrophilic surface was obtained on 2024 and 6061 aluminum alloy substrates by anodic oxidation，reaming and coating of sodium fluosilicate，and the surface morphology，elemental composition， wettability and electrochemical properties of the as-prepared hydrophilic surface were analyzed. Results showed that after anodizing with 15%(mass fraction) sulfuric acid solution， the oxide films of 2024 aluminum alloy and 6061 aluminum alloy presented the rough nano-particles and dispersed micropores respectively. And the oxide film of 2024 aluminum alloy could better combine with sodium fluorosilicate to form a surface film with good hydrophilic effect. These two kinds of aluminum alloys were coated in sodium fluorosilicate solution， and hydrophilic films with contact angles less than 30° were obtained. The average contact angle of 2024 aluminum alloy surface was 18.5° and both aluminum alloys obtained good hydrophilicity. The electrochemical test results showed that the corrosion resistance of 2024 and 6061 aluminum alloys both decreased after coating， and the corrosion resistance of 6061 aluminum alloy changed more obviously. In all， the hydrophilicity and corrosion resistance of 2024 aluminum alloy were better than those of 6061 aluminum alloy after coating.