Corrosion Behavior of Anodized 2195 Al-Li Alloys with Different Sealing Methods

Abstract

The influence of post-sealing treatment on corrosion behavior of anodized 2195 Al-Li alloys was studied by potentiodynamic polarization, Electrochemical Impedance Spectroscopy(EIS),salt spray test and immersion test in solution of phosphoric acid/chromic acid. The anodic films were post- treated with boiling water, potassium dichromate, nickel sulfate and cerium nitrate, respectively. The results show that the post- sealing can greatly enhance the corrosion resistance of the anodized 2195 Al- Li alloy. The corrosion resistance of the anodic oxide film after post- treatment with cerium nitrate is far better than that with boiling water, but slightly inferior to those with potassium dichromate and nickel sulfate. Finally long term spray test results reveal that the anodized 2195 Al-Li alloy after sealing treatment with potassium dichromate exhibits the highest corrosion resistance among the four post-sealing treatments.