Coatings with only passive protection cannot offer long-term anticorrosion on metals. Eco-friendly sustainable and responsive coating for active/passive corrosion protection is desirable to extend the service life of metals. Here, benzotriazole (BTA)-metal organic frameworks (Cu-MOFs, UiO-66) were embedded in silica (SiO2) coating by one-step electrodeposition on copper. Combined with passive capability of MOFs and active protection of BTA inhibitor, the composite coating (BTA-MOF/SiO2) exhibited high and stable corrosion resistance, confirmed by microstructure characterizations and electrochemical tests. As a result, the as-prepared composite coating exhibited superhydrophobicity with a water contact angle of 154.2°. With loading of BTA-MOF in SiO2 coating, the impedance modulus at 0.01 Hz increased by ∼10-fold and the corrosion current density decreased to 3.472 × 10–9 A·cm–2. Immersion and salt spray tests confirmed the long-term protection of the composite coating. The responsive release of BTA inhibitor endows the coating with a responsively anticorrosive behavior. The active-passive ability makes the coating a good candidate for protection on metals used in highly salty environments.
Yue Zhao,Da-Peng Wang,Guang-Long Zhang,Jin-Wei Zhang,Ji-Yong Zheng,Cun-Guo Lin
In this work, the carbon-based 2D-3D composite nanocontainers endowing coatings with both active and passive protection properties were constructed by the sp 2 /sp 3 hybridized carbon as a versatile strategy. The classic graphene oxide (GO, sp 2 C) and Covalent Organic Framework-300 (COF-300, sp 3 C) were chosen as examples and benzotriazole (BTA) as the inhibitor to fabricate the GO/COF-300@BTA nanocontainer. The composite nanocontainers embedded in polyvinyl butyral (PVB) coatings were applied on cupper substrates to get mechanical enhancement, active and passive corrosion protection performance. The tensile strength of GO/COF-300/PVB (12.38 Mpa) was two times higher than that pure PVB (5.96 MPa). The active protection performance was ensured by the corrosion inhibitors encapsulated in the 3D porous carbon skeleton. The passive protection performance was endowed by the maze effect of the 2D carbon-based nanosheets. The |Z| 0.01 Hz of Cu/(GO/COF-300@BTA)/PVB was higher than 10 9 Ω·cm 2 , which was two magnitudes larger than that of PVB coating, demonstrating the anti-corrosion properties. In addition, the quantum chemical calculation and molecular dynamics simulation results elaborated the adsorption states of BTA on copper substrate and the compatibility between the molecular chains of the PVB and the GO/COF-300 nanocontainer.