Nanoparticles with Core-Shell structure as efficient recoverable corrosion inhibitors for mild steel in acidic media

The challenge of mild steel corrosion under acidic conditions remains a critical challenge in industrial operations, necessitating the development of effective anti-corrosion technologies. To overcome this problem, there is an urgent need for efficient corrosion inhibitors. This research explored the corrosion inhibition ability of core-shell structured polydopamine (PDA)@silicon dioxide (SiO₂)@Fe₃O₄ magnetic nanoparticles (MNPs) for mild steel in 1 M HCl solution. Weight loss measurements demonstrated PDA@SiO₂@Fe₃O₄ MNPs achieved a 96.57 % inhibition efficiency, with 88.09 % efficiency retained after recycling. Electrochemical analysis confirmed its mixed-type inhibition mechanism, suppressing both anodic and cathodic reactions. The adsorption behavior of the inhibitor followed the Redlich-Peterson (R-P) isotherm model, indicating a hybrid interaction mechanism involving both physical adsorption and chemical bonding between the MNPs and the mild steel surface. Comprehensive analysis revealed that the PDA and SiO₂ layers effectively protected the magnetic Fe₃O₄ core, allowing the PDA@SiO₂@Fe₃O₄ MNPs to remain stable in the HCl solution while exhibiting enhanced corrosion inhibition performance. This research presents a novel strategy for developing recyclable nano-corrosion inhibitors suitable for acidic conditions.