Preparation and Performance of a New Trivalent Chorme Light Blue Passive Film

A new trivalent chorme light blue passive film was prepared on the surface of galvanized plate under different passivation conditions by adding organic silicone resin into a traditional inorganic passivation solution.The structure and surface morphology of the passive film were characterized by infrared spectroscopy and scanning electron microscopy.Corrosion resistance of the passive film was studied using electrochemical test,copper sulfate pitting test and neutral salt spray test.The results show that an organic-inorganic hybrid passive film with good corrosion resistance,high density and adhesion was formed on the surface of the galvanized plate,which greatly improved the corrosion resistance of the galvanized plate.The passive film prepared at passivation temperature of 30℃,passivation time of 30 s,passivation solution pH of 1.8,had the most compact structure and best corrosion resistance.The pitting time in copper sulfate pitting test was 20 s,and the rust occurrence time in neutral salt spray test reached 200 h for this passive film.