INFLUENCE OF THE MOLAR RATIO ON THE ELECTROCHEMICAL BEHAVIOR OF WATERBORNE POTASSIUM SILICATE ZINC-RICH COATING

The influence of the molar ratio(SiO2/K2O molar ratio) of potassium silicate solution on the electrochemical behavior of waterborne zinc-rich coating were studied by monitoring the variation of the corrosion potential(Ecorr) of the coatings and the electrochemical impedance spectroscopy(EIS) . With the promotion of SiO2/K2O molar ratio,the results showed that the shield effect of impenetration of corrosion medium to substrate was enhanced and the dissolution resistance of zinc particles in the coatings was increased with the Ecorr of the coatings. Besides,scanning electron microscope(SEM) was used to characterize the surface structure of the coatings with different SiO2/K2O molar ratio. While the SiO2/K2O molar ratio of waterborne inorganic potassium silicate zinc-rich paint increasing,the binding among Zn particles was reinforced,the intensity of the coatings was strengthened and gaps among the coatings decreased to form denser coating structure.