Green and sustainable chitosan-gum Arabic nanocomposites as efficient anticorrosive coatings for mild steel in saline media

The application of green and sustainable anticorrosive coatings is becoming of upsurge interest for the protection of metallic materials in aggressive environments. Herein, a stable crystalline chitosan/gum Arabic composite (CGAC) nanopowder was successfully synthesized and characterized by various methods. The CGAC nanopowder with different doses (25, 50, 100, and 200 ppm) was used to coat mild steel samples and examined its anticorrosion ability in 3.5 wt.% NaCl solution using gravimetric, electrochemical measurements, and surface characterization techniques. All methods yielded consistent results revealing that nanocomposite coatings can impart good anticorrosive properties to the steel substrate. The obtained protection efficiency was enhanced with increasing CGAC dose in the applied surface layer achieving 96.6% for the 200 ppm-coating. SEM and AFM surface morphologies of uncoated and coated samples after the inundation in the saline solution showed that CGAC coating can block the active corrosive sites on the steel surface, and prevent the aggressive Cl- ions from attacking the metallic substrate. The water droplet contact angle gave further support as it increased from 50.7 degrees for the pristine uncoated surface to 101.2 degrees for the coated one. The current research demonstrates a promising natural and reliable nanocomposite coating for protecting mild steel structures in the marine environment.

Automated summary

The application of green and sustainable anticorrosive coatings for metallic materials is of growing interest. In this study, a stable crystalline chitosan/gum Arabic composite (CGAC) nanopowder was successfully synthesized and tested for its anticorrosion ability on mild steel. The results showed that the nanocomposite coating provided good corrosion resistance, with higher doses of CGAC resulting in increased protection efficiency. Additionally, the coating was found to block corrosive sites on the steel surface and protect against aggressive chloride ions.