Investigating about the Effect of Phosphating Liquid on the Corrosion Resistant of Phosphating Film of Aluminium Alloy

The electrochemical character of Zinc Phosphating Coating for aluminum alloy was studied by electrochemical tests.The influence of change in the content of Fe(H2PO4)2·2H2O,Ni(NO3)2·6H2O,H3C6H5O7H3PO4,citric acid on the corrosion resistant of zinc phosphating coating was researched.The results showed that,when the combination is Fe(H2PO4)2·2H2O 4g/L,Ni(NO3)2·6H2O 1.5g/L,H3C6H5O71.5g/L,H3PO4,3.5g/L linear polarization resistance is max and the corrosion resistance is best.