Corrosion Inhibition Performance of 2-Aminothiophene-3-carboxamide for Copper in 3.5 wt.% NaCl Solution

Developing highly efficient organic corrosion inhibitors plays a crucial role in enhancing copper's resistance to degradation in aggressive environments. This research evaluates the corrosion inhibition efficacy of 2-aminothiophene-3-carboxamide (2ATCA) at the copper interface in simulated seawater medium (3.5 wt% NaCl). The findings indicate that incorporating 0.60 g/L of 2ATCA into the NaCl solution leads to a significant drop in corrosion current density, from 12.1 μA·cm -2 to 1.7 μA·cm -2 , achieving an inhibition efficiency of 86%. The Langmuir adsorption isotherm model was derived by applying the thermodynamic principles governing the corrosion inhibitor's mechanism. The surface characteristics and composition of copper were characterized through a combination of analytical techniques including scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The adsorption inhibition mechanism and reactivity of 2ATCA on the copper surface were further investigated through theoretical computational analysis. This study not only elucidates the adsorption behavior and mechanism of 2ATCA on copper but also provides a foundation for designing more effective organic inhibitors for copper corrosion in marine environments. • 2ATCA achieves 86% corrosion inhibition efficiency for copper in 3.5 wt% NaCl at 0.60 g/L. • Adsorption follows the Langmuir isotherm with mixed physisorption and chemisorption. • SEM, AFM, FTIR, and XPS confirm formation of a dense adsorbed layer on copper. • DFT identifies N and S atoms as primary reactive sites; MD shows parallel adsorption on Cu(111). • Combined experimental and computational studies elucidate the inhibition mechanism.