Corrosion Resistance Evaluation of Anodic Films on Aluminum Alloys Sealed with Several Processes by Different Methods

The corrosion resistance of anodic films on aluminum alloys sealed with cerium salt was studied by using mass loss immersion testing in phosphoric-chromic acid solution,metallic coatings-copper accelerated acetic acid salt spray testing (CASS testing) and electrochemical methods,and compared with the anodic films sealed by the methods of nickel fluonide,potassium dichromate and boiling water.The mass loss rate of aluminum alloy anodic film sealed with cerium salt was lower than 30 mg/dm2 after immersing in phosphoric-chromic acid solution,which matched the Chinese Standard GB/T5237.2-2000.The results of CASS testing and electrochemical methods showed that the corrosion resistance of aluminum alloy anodic film sealed with cerium salt was close to that of aluminum alloy anodic films sealed with other methods.The rare-earth salt sealing method is environmental friendly and can get the film with good performance.Its application prospect is very good.