Physico-mechanical and electrochemical corrosion behavior of soy alkyd/Fe3O4 nanocomposite coatings

Abstract

The present article reports the synthesis of butylated melamine formaldehyde (BMF) cured soy alkyd (SA-BMF) and nanoferrite (Fe₃O₄) dispersed SA-BMF (SA-BMF–Fe₃O₄) nanocomposite anticorrosive coatings. The structural elucidation of SA-BMF and SA-BMF–Fe₃O₄ was performed by Fourier transform infra-red (FT-IR) spectroscopy. Physico-mechanical properties such as impact resistance, bend test, scratch hardness, cross hatch adhesion test of these coatings were analyzed by standard protocols. Thermogravimetric analysis (TGA) was used to evaluate the thermal stability of the coating material. The corrosion resistance performance of SA-BMF and SA-BMF–Fe₃O₄ coated CS was evaluated by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques in 3.5 wt% NaCl solution. The salt spray test for coated and uncoated carbon steel (CS) strips in 5 wt% NaCl solution was also performed. Study revealed that the presence of Fe₃O₄ nanoparticles played a prominent role in the performance of SA-BMF matrix as reflected by high thermal stability, good hydrophobicity, enhanced physico-mechanical properties and higher corrosion resistance performance. Among different compositions, SA-BMF–Fe₃O₄-2.5 coatings exhibited far superior physico-mechanical and corrosion inhibition properties than SA-BMF coatings and other similar reported systems. The possible mechanisms of corrosion inhibition by nanocomposite coatings are also discussed.