Comprehensive study on the corrosion inhibition of aluminum in HCl by N1, N1'-(ethane-1,2-diyl)di(ethane-1,2-diamine): Experimental and theoretical approaches

Abstract

The inhibitory effects of the novel molecule N1, N1'-(ethane-1,2-diyl)di(ethane-1,2-diamine) (TETA) on aluminum (Al) corrosion were investigated in 0.2, 0.3, and 0.4 M HCl solutions. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), quantitative techniques, and surface morphology characterisation were utilised. Surface morphology characterisation via atomic force microscopy (AFM) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) confirmed the efficacy of the inhibitor in preventing corrosion. Weight loss research revealed that the protective efficacy of TETA grows with increasing concentration but shrinks with increasing temperature of the acidic solution. The findings indicate a marked increase in inhibition efficiency as TETA content rises, reaching 99.0 % when measured by the weight loss method, 98.34% through EIS, and 94.13% via electrochemical polarization. Polarization curves show that TETA stops hydrochloric acid from acting on the anodic type. Both the charge-transfer resistance and the double-layer capacitance decrease with increasing inhibitor concentration, as shown by the adsorption mechanism and supported by the EIS results. ''The Langmuir isotherm and negative Gibb's free energy values demonstrate that the inhibitor molecules cling to the metal and that they adsorb to the aluminium spontaneously. In addition to analysing TETA via density functional theory (DFT), the adsorption of TETA on the surface of aluminium (Al) was examined via molecular dynamics (MD) simulations. The results show that the TETA molecule successfully blocks the corrosion process.

Keywords

• Aluminum
• Corrosion inhibitor
• N1,N1'-(ethane-1,2-diyl)di(ethane-1,2-diamine) (TETA)
• Density functional theory
• Electrochemical impedance spectroscopy
• Molecular dynamics