Synthesis of novel waterborne silicone modified acrylic sealant and its corrosion resistance in Fe-based amorphous coatings

Porosity defects inevitably existed in the atmospheric plasma spraying (APS) Fe-based amorphous coatings, which directly affected the service lives of the coatings. Thus, sealing treatment became an effective method to improve the coatings' corrosion resistance and prolong their service lives. In this study, a waterborne silicone modified acrylic emulsion (WAE) was synthesized by emulsion polymerization and used as the main film-forming to prepare a waterborne silicone modified acrylic sealant (WAS) with both sealing and anticorrosion. Heat resistance analysis showed that the maximum decomposition temperature of WAS was 409 °C. Energy Dispersive Spectroscopy (EDS) test indicated that the water sealant penetrated to a depth >70 μm. Potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) investigated the long-term corrosion resistance of the sealed coating. The results show that the waterborne sealant promotes the integrity of the passive film of the coating after sealing with the waterborne silicone modified acrylic sealant. After immersion for 34 days, the corrosion current density of the sealed coating decreased by more than one orders of magnitude (SR-3, icorr = 6.3 × 10−4A/cm2; Sample 0, icorr = 7.2 × 10−3A/cm2), and the coating protection efficiency (η) remained above 90 %. Considering the solvent-free property and excellent long-term corrosion resistance of the sealant, it provides a new direction for the research and development of functional waterborne coating.