Preparation and Corrosion Resistance of Cerium and Silane Composite Passivation Film on Electrolytic Manganese Surface

The cerium and silane composite passivation film on the surface of electrolytic manganese was successfully fabricated by immersing in passivation solution which was a mixture of silane coupling agent KH550 and cerium nitrate. The composite passivation film was characterized and analyzed through polarization curve, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). It was found that the corrosion potential of electrolytic manganese increased from -1.364 V before passivation to -1.225 V after passivation, the corrosion current density decreased from 3.58×10^-5 A/cm² to 1.91×10^-6 A/cm², the polarization resistance increased from 461.18 Ω·cm² to 4 706 Ω·cm², and the current blocking efficiency reached 94.66%. The prepared passivation film could significantly improve the corrosion resistance of electrolytic manganese.