Performance Ag/CNT-PVC coatings for corrosion protection of Zn and Al in nitric acid environments

Corrosion in acidic environments significantly reduces the durability of metallic substrates such as zinc (Zn) and aluminum (Al). Traditional polymer coatings, such as polyvinyl chloride (PVC), provide limited protection. This study developed a novel nanocomposite coating system integrating silver-decorated carbon nanotubes (Ag/CNTs) and potassium iodide (KI) into a PVC matrix to enhance corrosion resistance. The Ag/CNTs were synthesized by chemical reduction and uniformly dispersed in PVC via solution casting. Key challenges addressed include achieving homogeneous dispersion, ensuring strong adhesion to substrates, and balancing electrical conductivity with barrier properties. The coating’s performance was assessed using gravimetric analysis, electrochemical measurements, and resistance tests. Advanced techniques such as transmission electron microscopy and scanning electron microscopy characterized the nanostructure and morphology. Optimization of coating parameters was performed using Response Surface Methodology. The synergistic Ag/CNT/PVC-KI coating significantly outperformed pure PVC coatings, reducing corrosion rates by 58.9% for Zn and 69.7% for Al in 1 M nitric acid. The coating also demonstrated excellent barrier properties, with resistance values up to 18 kΩ and consistent structural integrity. These findings highlight the potential of nanocomposite-enhanced coatings for robust corrosion protection in harsh chemical environments.