The protective performance of ZrP/epoxy resin intelligent coating steel bars based on chloride ion response mechanism

To address the critical issues of uncontrolled inhibitor release and low protection efficiency in traditional steel reinforcement coatings, this study innovatively developed an intelligent anticorrosive coating system based on a chloride-responsive mechanism. The intelligent responsive filler LCZrP-Ag-SA was successfully prepared by intercalating L-arginine (LA) corrosion inhibitor into two-dimensional layered zirconium phosphate (ZrP) and encapsulating it with a chloride-triggered sodium alginate-silver nitrate (Ag-SA) shell. This filler was then incorporated into an epoxy resin (EP) matrix to construct an environmentally responsive intelligent anticorrosive coating. The results demonstrate that the coating enables directional and controllable inhibitor release in chloride-containing environments. In simulated corrosion experiments on artificially scratched coating-steel specimens, the low-frequency impedance modulus (|Z|_0.01Hz) of the LCZrP-Ag-SA/EP coating was 37 times higher than that of the conventional EP coating. The chloride-triggered response mechanism facilitated targeted inhibitor release, significantly reducing corrosion products at the defect sites. During the 60-day long-term evaluation, the |Z|_0.01Hz of LCZrP-Ag-SA/EP coated steel specimens remained stable within the range of 6.00×10⁹~7.11×10⁹ Ω·cm². The synergy of the intelligent filler and the resin coating system enhanced the protective performance by 19 times compared to the traditional EP coating's |Z|_0.01Hz value during the same period. This study provides an innovative solution for improving the durability of reinforced concrete structures in marine environments.