Investigation of the Corrosion Protection Properties of Reinforced Epoxy Resin With Clay Nanoparticles on Mild Steel

This study investigates the corrosion protection performance of epoxy coatings reinforced with clay nanoparticles applied to mild steel substrates, particularly in acidic environments relevant to industrial settings. Locally sourced clay was synthesized into nanoparticles using a top-down mechanical grinding approach and incorporated into epoxy resins at varying concentrations (1–5 wt.%). The experimental design employed was Response Surface Methodology (RSM) using MINITAB software to optimize the effects of three factors—clay concentration, hydrochloric acid concentration, and exposure time on corrosion resistance .Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarization (PDP) were used to assess the corrosion resistance of the coatings. Results showed that coatings with higher clay content, particularly at 5 wt.%, exhibited significantly higher charge transfer resistance (Rp), indicating superior protective efficiency. The optimal sample achieved an Rp of 591.4 Ω, slightly exceeding the predicted 564.76 Ω with about 4.7%, confirming the reliability of the RSM model. SEM analysis of the nanoparticles showed high surface area and uniform dispersion, contributing to reduced porosity and enhanced barrier properties. Additional mechanical testing revealed superior hardness (85.9 HRC) and adhesion (ASTM 3B rating) for the optimized clay-reinforced coating compared to conventional paints.The findings affirm the feasibility of using eco-friendly, locally available clay nanoparticles to improve the durability and performance of protective coatings.