Self-healing anticorrosion one-step electrodeposited layered double hydroxide coating on steel rebar in concrete pore solution

A phosphate-intercalated layered double hydroxide (PO 4 -LDH) coating was fabricated on carbon steel via a facile one-step electrodeposition method for enhanced corrosion protection. The resulting nanoscale coating, incorporating PO₄³⁻ ions and Cu/Al oxides, exhibits improved integrity and compactness. Electrochemical tests in saturated Ca(OH)₂ solution (simulating concrete pore environment) demonstrated that the PO 4 -LDH coating significantly improves corrosion resistance, offering protection two orders of magnitude greater than bare steel. The coating effectively prevents corrosion upon chloride attack and exhibits self-healing capability for artificial scratches in chloride-containing solution. During immersion, the LDH structure reconstructs via dissolution of Al and incorporation of Ca, leading to increased crystallinity. The release of inhibitor ions (PO₄³⁻ and NO₃⁻) during this reconstruction is considered the key mechanism for the observed anticorrosion and self-healing performance.