New hybrid composite coatings (HCCs) on hot-dip galvanized steel (HDGS) were obtained using electrophoresis (cathodic polarization (CP)) and sol-gel technology. For this purpose, a technique for the preparation of a cationic precursor based on TiCl4 and aminopropyltriethoxysilane was developed. Electrophoresis of the charged particles of the precursor and organosilanes promotes the production of denser sol-gel coatings with improved adhesion. Using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) methods, the formation mechanism and protective properties of HCC on galvanized steel were investigated.
Keywords: corrosion; electrophoresis; galvanized steel; organosilanes; phosphonates; sol–gel coatings.