Chromate-free Passivation Technology for Electrodeposited Nickel Coating

In order to improve the corrosion resistance of electrodeposited nickel coating and subsititute the carcinogenic hexavalent chromium passivation, a new chromate-free passivation solution was screened out by means of orthogonal analysis experiments. The solution was composed of phytic acid, sodium molybdate and corrosion inhibitor. The optimal time for conversion film formation was determined by electrochemical impedance spectroscopy. The corrosion resistant properties of electrodeposited nickel coating were studied by dropping corrosion test in 5% CuSO4, immersion test in 10% NaCl and polarization curves. The results showed that the film passivated by the technology has good anti-corrosion performance.