Characterization of a tetrafunctional epoxy-amine coating for corrosion protection of mild steel

Epoxy resins are one of the most widely used thermosetting materials in industrial and practical applications because they exhibit excellent mechanical, thermal, and dielectric performance at commodity volume and cost. In particular, multifunctional epoxies—dense and cross-linked structured resins—are used as molding compounds, sealants, and protective coatings for many barrier-related applications. In this work, we used a tetrafunctional epoxy-amine resin as a coating for mild steel and used electrochemical impedance spectroscopy (EIS) to investigate its protection performance in a 3.5 wt % NaCl solution. The results indicate that the coating was able to resist corrosion and maintain a very high impedance modulus for more than 30 d of continuous exposure to the NaCl solution. Different resistance behaviors, as indicated by EIS, were observed for the coatings with artificially introduced damage. The coating also showed high thermal resistance and good adhesion to mild steel surfaces. This tetrafunctional epoxy-amine resin could effectively function as a high performance and corrosion resistant coating material for semiconductor, aerospace, and marine applications.