Institute for Color Science and Technology (ICST) Progress in Color, Colorants and Coatings 2008-2134 19 1 2025 09 01 Corrosion Protection of Mild Steel in Acidic Media by a Triazole-Based Inhibitor: Mechanistic Insights and Performance Evaluation 9 22 82098 10.30509/pccc.2025.167535.1392 EN N. A. Al-Ali Biomedical Engineering Department, University of Technology, Baghdad P.O. Box: 10001, Baghdad, Iraq A. Al-Amiery Biomedical Engineering Department, College of Engineering, Al-Ayen University (AUIQ), Nile St, Nasiriyah P.O. Box: 64001, Dhi Qar, Iraq Journal Article 2025 04 29 The present work investigates the corrosion inhibition behavior of 4-(4-methoxybenzylidene)amino-5-pyridin-3-yl-3-thio-1,2,4-triazole (MAPTT) on mild steel in 1 M HCl using the weight loss method over a range<br />of concentrations (0.1-1.0 mM) and immersion durations (1-48 hours).<br />The inhibition efficiency (IE%) was found to rise with increasing inhibitor concentration, achieving a maximum value of 92.7% at 0.5 mM after 48 hours. Although a gradual improvement in efficiency was observed with longer <br />immersion periods, it tended to stabilize after 10 hours. Investigations at different temperatures (303–333 K) over a 5-hour immersion period revealed a slight improvement in inhibition efficiency, suggesting good thermal stability of MAPTT. The process of adsorption obeyed Langmuir model, referring to a combination of chemical and physical adsorption mechanisms. In comparison with previously reported inhibitors, MAPTT demonstrated superior performance, attributed to its strong adsorption and stable protective film formation at elevated temperatures, ensuring sustained corrosion resistance. Density Functional Theory (DFT) predictions, having the analysis of HOMO and LUMO orbitals, identified active adsorption centers within the molecule. Furthermore, the calculated band gap in addition to electron transfer fraction (Δ𝑁) supported the strong interactions between MAPTT and specimen surface. The excellent correlation of experimental techniques and theoretical DFT calculations highlights the promise of MAPTT as a thermally robust and highly efficient corrosion inhibitor for industrial use in corrosive solution.  https://pccc.icrc.ac.ir/article_82098_6104d1589009e4da78fbdc28ebae9905.pdf