Gallic acid-infused LDH nano-containers: A durable protection against mild steel corrosion in simulated seawater

A novel low-dimensional composite nanoparticle is created by using magnesium/aluminum layered double hydroxide (Mg|Al LDH) as a carrier for Gallic acid (GA). The GA is then integrated into the LDH, forming LDH/ GA, at varying ratios. These composite systems are then evaluated for their ability to prevent corrosion on steel substrates in a neutral 3.5 wt.% NaCl environment at different concentrations. To understand the structural changes, the chemical composition of GA, LDH, and the crystal structures of LDH/GA are examined using Fourier-transform infrared spectroscopy (FT-IR) and X-Ray diffraction (XRD) and Ultraviolet-visible (UV-Vis) tests. Also, the corrosion inhibition performance of these composite particles is assessed using Electrochemical impedance spectroscopy (EIS) and polarization tests, helping to elucidate the protective mechanism. The morphology of both corroded and protected substrates is visualized using Field Emission Scanning Electron Microscope (FE-SEM). EIS and polarization results indicate that the incorporation of 800 ppm GA into LDH significantly improves the corrosion inhibition performance, achieving up to 73 % and 78 % inhibition, respectively. Contact angle measurements reveal that the corroded samples exhibit hydrophilic characteristics, while the formation of a GA layer enhances their hydrophilicity. Increasing the concentrations of GA and LDH/GA also results in a higher degree of hydrophilicity.