High-performance self-healing anticorrosion coating base on mesoporous SiO2/g-C3N4 nano-containers for Q235 steel

A smart anti-corrosion and self-healing coating BTA@MSNs/g-C 3 N 4 @PDA was prepared base on mesoporous silica nanoparticles (MSNs) and graphite-phase carbon nitride (g-C 3 N 4 ) composites as nano-containers and loaded the corrosion inhibitor benzotriazole (BTA), as well as wrapped polydopamine (PDA). The structure and properties of the composites were characterized by SEM, TEM, EDS, FT-IR, XPS, XRD and N 2 physical adsorption. The release behaviors of BTA were tested by UV–Vis spectroscopy. Then these prepared materials were mixed to epoxy resin E-51 (EP) and cured to obtaining three protective coatings of MSNs/g-C 3 N 4 -EP, BTA@MSNs/g-C 3 N 4 -EP, and BTA@MSNs/g-C 3 N 4 @PDA-EP. These coatings were used as working electrodes to investigate their anti-corrosion and self-healing properties via electrochemical impedance spectroscopy (EIS), salt spray test, SEM and EDS. Test results indicate that the smart coatings presented better corrosion-resistant and self-healing performance. After being soaked in 3.5 % NaCl solution for 30 days, the |Z| 0.01Hz value of the coating BTA@MSNs/g-C 3 N 4 @PDA-EP could still reached to 10 6 , two orders of magnitude higher than that of the coating MSNs/g-C 3 N 4 -EP. Furthermore, the self-healing mechanism of these coatings was also better explored. In summary, this study will provide feasible paths and guidance for the preparation of intelligent anticorrosive self-healing new materials.