Influence of Silane Content on Protective Performance of Thin Organic Coating on Automotive Galvanized Steel

Aiming at improving protective performance of thin organic coatings on automotive galvanized steels, the epoxy silane was used as a cross-linking agent, and waterborne acrylic resin as a film ingredient. Effect of silane content on morphology, water resistance and corrosive resistance properties were investigated using reflectivity tester, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The influence of silane content on the protective performance of the coating was analyzed by electrochemical impedance spectroscopy. The results showed that when the mass fraction of silane in the coating was less than 1.00%, with the increase of silane content, the water resistance and corrosive resistance of the coating were significantly improved, and the protective performance of the coating to the steel plate was enhanced. When the mass fraction of silane exceeded 1.00%, silane could not be completely integrated into the coating, which led to defects in the coating and reduced its protective ability.