Enhanced Adhesion and Corrosion Protection Properties of Surface Modified Sb2O3–Epoxy Nanocomposite Coatings on Mild Steel

The effect of introducing Sb2O3 (antimony oxide) nanoparticles in epoxy coatings on mild steel was analyzed by electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) techniques in 3.5% NaCl. In order to disperse the nanoparticles properly and enable the interactions of nanoparticles chemically with epoxy resin, (3-mercaptopropyl)trimethoxysilane (MPTMS) was used to modify the nanoparticle. The charge transfer resistance (Rct) and the film resistance (Rf) were improved by incorporating Sb2O3 nanoparticles in the epoxy coating. The dissolution of iron at the scratch was detected using proper potential at the tip of the SECM in the Sb2O3-incorporated nanocomposite-coated sample. The presence of concentrated Sb was found in the scratched surface and examined by SEM/EDX analysis. FIB–TEM technique confirmed the elements present in the degradation products. The higher anti-corrosion properties of Sb2O3-grafted epoxy coating were achieved because surface modified Sb2O3 nanoparticles interacted chemically with the epoxy resin, which resulted in the deposition of the degradation products in the nano-level at the scratch.