Aluminum alloy 2024-T3 is widely used in aerospace and marine applications due to its excellent mechanical properties, but its susceptibility to corrosion in chloride-rich environments presents a major challenge to its long-term durability. This study looks at how well bisphenol S tetraglycidyl ether dianiline dipropoxy (TGEDADPDS) epoxy resin protects AA2024-T3 aluminum alloy when it is placed in a 3.5% NaCl solution, using both experiments and theoretical methods. Tests showed that TGEDADPDS is a very effective corrosion blocker, working better at higher amounts, reaching a maximum protection level of 95.8% when used at a concentration of 10−3 M, and reducing the corrosion current density from 23 to 1.2 µA/cm2. Electrochemical impedance spectroscopy (EIS) results corroborated these findings, showing a significant increase in polarization resistance from 870 to 16,223 Ω cm2. Temperature dependence studies revealed a moderate reduction in inhibition efficiency at higher temperatures, retaining 88% efficiency at 328 K. Thermodynamic assessments indicated increased activation energy (from 22 to 44.73 kJ/mol) and enthalpy (from 19.4 to 42.13 kJ/mol), along with a decrease in entropy, suggesting the formation of a more ordered inhibitor-metal interface. Adsorption behavior followed the Langmuir isotherm (R2 = 1), indicating spontaneous, monolayer adsorption with a free energy of adsorption (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10853_2025_11226_Article_IEq1.gif" Format="GIF" Height="22" Rendition="HTML" Resolution="72" Type="Linedraw" Width="45" /> </InlineMediaObject> <EquationSource Format="TEX">$\Delta {\text{G}}_{{{\text{ads}}}}^{^\circ }$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="normal">Δ</mi> <mmultiscripts> <mtext>G</mtext> <mrow> <mtext>ads</mtext> </mrow> <mmultiscripts> <mrow /> <mrow /> <mo>∘</mo> </mmultiscripts> </mmultiscripts> </mrow> </math></EquationSource> </InlineEquation>) of − 45.25 kJ/mol. Density functional theory (DFT) calculations demonstrated favorable electronic properties of TGEDADPDS, while Monte Carlo (MC) simulations revealed a strong adsorption energy (− 276.15 kcal/mol). Scanning electron microscopy/ Energy dispersive X-ray spectroscopy (SEM/EDS) analyses confirmed smoother surface morphology and reduced corrosive element content after treatment. Collectively, these results underscore TGEDADPDS’s potential as an effective, thermally stable, and surface-active corrosion inhibitor suitable for protecting aluminum alloys in marine environments.

Novel sulfur epoxy-based protection of aluminum alloy in marine conditions: a combined electrochemical and computational study

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发表日期：

2025年8月4日

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Abdeslam El Amri,
Naoual El-Aouni,
Omar Dagdag,
Hansang Kim,
Anvi Berisha,
Rajesh Haldhar,
Moussa Ouakki,
Mohamed Rafik,
Khalil El Mabrouk,
Mohamed Ebn-Touhami,
Seong-Cheol Kim,
Nadia Dkhireche

摘要

Aluminum alloy 2024-T3 is widely used in aerospace and marine applications due to its excellent mechanical properties, but its susceptibility to corrosion in chloride-rich environments presents a major challenge to its long-term durability. This study looks at how well bisphenol S tetraglycidyl ether dianiline dipropoxy (TGEDADPDS) epoxy resin protects AA2024-T3 aluminum alloy when it is placed in a 3.5% NaCl solution, using both experiments and theoretical methods. Tests showed that TGEDADPDS is a very effective corrosion blocker, working better at higher amounts, reaching a maximum protection level of 95.8% when used at a concentration of 10⁻³ M, and reducing the corrosion current density from 23 to 1.2 µA/cm². Electrochemical impedance spectroscopy (EIS) results corroborated these findings, showing a significant increase in polarization resistance from 870 to 16,223 Ω cm². Temperature dependence studies revealed a moderate reduction in inhibition efficiency at higher temperatures, retaining 88% efficiency at 328 K. Thermodynamic assessments indicated increased activation energy (from 22 to 44.73 kJ/mol) and enthalpy (from 19.4 to 42.13 kJ/mol), along with a decrease in entropy, suggesting the formation of a more ordered inhibitor-metal interface. Adsorption behavior followed the Langmuir isotherm (R² = 1), indicating spontaneous, monolayer adsorption with a free energy of adsorption ( $\Delta {\text{G}}_{{{\text{ads}}}}^{^\circ }$ $Δ G_{ads}^{^{\circ}}$ ) of − 45.25 kJ/mol. Density functional theory (DFT) calculations demonstrated favorable electronic properties of TGEDADPDS, while Monte Carlo (MC) simulations revealed a strong adsorption energy (− 276.15 kcal/mol). Scanning electron microscopy/ Energy dispersive X-ray spectroscopy (SEM/EDS) analyses confirmed smoother surface morphology and reduced corrosive element content after treatment. Collectively, these results underscore TGEDADPDS’s potential as an effective, thermally stable, and surface-active corrosion inhibitor suitable for protecting aluminum alloys in marine environments.