Experimental and multiscale simulation studies on Chitosan doped Hybrid/Zirconium-a bio-nanocomposite coating for aluminium protection

Aluminum metal and its alloys are most precious metals in industries, marine, and aircraft applications due to its interesting properties. However, aluminum metal undergoes corrosion in presence of aggressive chloride environments. Sol-gel based protective coating is mainly used to safeguard aluminum metal from corrosive chloride environments. In the present work, inorganic and polymeric composite corrosion inhibitors were synthesized for Al protection in aqueous 3.5% NaCl media (Zr and chitosan were hybridized using silanes). Surface morphology and chemical composition were duly characterized via FTIR and SEM-EDX, while corrosion resistivity was investigated by impedance (EIS) and polarization studies (PDS). Further, molecular modeling studies were performed to understand the corrosion inhibition mechanism and reveal those factors influences the corrosion efficiency of the chitosan-doped hybrid corrosion inhibitors.Chitosan-doped Hy/Zrnanocomposite sol-gel coating shown higher corrosion resistance of 96.1% than a hybrid (Hy) and Hy/Zr sol-gel coating. PDS showed that the chitosan-doped Hy/Zr sol-gel coating protects the Al metal by an anodic dissolution process. Computational chemistry and molecular dynamics study further evident the chitosan-doped Hy/Zr sol-gel coating enhanced the corrosion resistance of the Al substrates by lowering the molecular orbital gap energy and enhancing the adsorption of the corrosion inhibitors.

Automated summary

This study successfully enhanced the corrosion resistance of aluminum metal in chloride environments through the synthesis of composite corrosion inhibitors. The analysis results showed that the chitosan-doped Hy/Zr nanocomposite sol-gel coating exhibited higher corrosion resistance compared to the hybrid (Hy) sol-gel coating and Hy/Zr sol-gel coating.