In-Situ Synthesis and Synergistic Anticorrosion Performance of the Sr5(PO4)3OH/Zn/Al-LDH Composite with an Intercalated Spherical Structure

Abstract

Capturing corrosive ions in corrosive media is an important method to inhibit corrosion. The strontium hydroxyphosphate/zinc/aluminum layered double hydroxide (Sr-HAP/LDH) composite with an intercalated spherical structure was effectively synthesized using the in-situ growth method, and it possesses multiple synergistic anticorrosion advantages. The combination of zinc/aluminum layered double hydroxide (Zn/Al-LDH) and strontium hydroxyphosphate (Sr-HAP) improves the specific capacitance, enhances electron storage, and reduces electron transfer, thereby lowering the corrosion rate. The intercalated spherical structure of the Sr-HAP/LDH composite effectively blocks electrolyte penetration. Additionally, through the Zn/Al-LDH immobilization mechanism and anion exchange, the Sr-HAP/LDH composite releases PO₄^3– from the interlayer to chelate with Fe²⁺ and Fe³⁺, while trapping the corrosive Cl^– ions within the interlayer. The electrochemical tests showed that the corrosion resistance of the Sr-HAP/LDH composite with multiple corrosion protections was 340.0% higher than that of epoxy resin and 190.4% higher than that of Sr-HAP coatings. This research offers an innovative approach for designing efficient anticorrosion materials, with significant theoretical implications and promising practical applications.