Enhancement of the Corrosion Resistance and Durability of Layered Double Hydroxide Films Through Incorporation of Polyelectrolytes and Dual Corrosion Inhibitors

Abstract

ABSTRACT The durability of layered double hydroxide (LDH) films is greatly improved by intercalating organic corrosion inhibitors, modifying the surface with polyelectrolytes, and uniformly doping with inorganic inhibitors. A LDH film was synthesized in situ on the aluminum surface with intercalated sodium polyaspartate (PASP‐Na) as an organic corrosion inhibitor. The film was then modified via a gelation reaction between sodium alginate (SA) and cerium ions (Ce), serving as an inorganic inhibitor, to form a composite coating with improved corrosion resistance and durability. Scanning electron microscopy (SEM) analysis revealed that the composite film had a thickness of approximately 4.9 µm and achieved a corrosion protection efficiency of 99.8%. This efficiency remained as high as 98.8% even after 28 days of immersion in a 3.5 wt% NaCl solution. SEM analysis of scratched samples demonstrated notable self‐healing capability. The self‐healing mechanism is due to PASP‐Na being released and adsorbed onto the scratched areas, along with water absorption by the SA‐Ce gel and Ce ions migrating to the damaged region.