Advancing imine metal chelates for corrosion inhibition across diverse environments: A novel perspective

Abstract

Using a suite of techniques, including potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and open circuit potential measurements, we investigated the corrosion resistance of transition metal chelates derived from Schiff base ligands against mild steel, copper oxide, aluminum, stainless steel, and high-carbon steel in acidic environments containing varying concentrations of hydrochloric acid, hydroxide ions, and sulfate ions at 25 °C. Spectral, quantitative, and physico-chemical analyses were employed to characterize the compounds under investigation. Our findings reveal a significant inhibition of corrosion across various steel substrates in the tested media by the studied compounds. Moreover, we observed an enhancement in corrosion inhibition efficacy with increasing concentrations of the investigated complexes. Notably, the negative values of Gibb's free adsorption energy (ΔG°ads) challenge the applicability of the Langmuir adsorption isotherm, suggesting a novel perspective on corrosion control mechanisms. Our study underscores the potential of Schiff bases and related transition metal chelates as effective corrosion inhibitors, providing insights into their utilization and factors influencing their application in corrosion mitigation strategies.