Abstract

Corrosion is a phenomenon that directly related to the environment. The surface protection by potential inhibitors is one of the possible solutions to combat metal/or metallic alloy corrosion. Here, we are reporting two 1,2,4-triazole-5-thione derivatives – 4-amino-3-(N-phthallimidomethyl)-1,2,4-triazole-5-thione (Tz-1) and 3-(N-phthalimidomethyl)-4-(4-pyridine)amino-1,2,4-triazole-5-thione (Tz-2) for corrosion inhibition performance on mild steel (MS) surface in 1 M HCl. Electrochemical experiments were carried for potentiodynamic polarization (PDP) and impedance spectroscopic (EIS) measurements of corroded MS surface before and after the addition of compound’s concentrations. Variations in the PDP responses and in the relevant parameters after compound’s addition confirmed that both Tz-1 and Tz-2 are mixed-type inhibitors. An increase in the diameter of a capacitive loop with inhibitor’s concentration in EIS studies revealed the formation of an adsorbed layer on the MS surface; hence protecting corrosion reaction by controlling the charge transfer process. The data obtained from PDP and EIS were reasonably in good agreement. The IE% (inhibition efficiency) of both Tz compounds showed increasing trend as inhibitor’s concentration was increased and the values were evaluated up to 95% and 94%, respectively, at their optimal concentration of 2.5 × 10⁻⁴ M. Adsorption studies using the Langmuir model further confirmed the involvement of physisorption process on MS in the presence of both compounds. Theoretical DFT (density functional theory) analysis results were supportive to comparatively more inhibitory efficiency of Tz-1. SEM (scanning electron microscopic) studies indicated more resistive behavior of MS surface for corrosion in the presence of Tz-1.

中文翻译：

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1,2,4-三唑-5-硫酮在酸性环境中对低碳钢1030的腐蚀电位

摘要

腐蚀是一种与环境直接相关的现象。潜在抑制剂的表面保护是应对金属/或金属合金腐蚀的可能解决方案之一。在这里，我们报告了两种1,2,4-三唑-5-硫酮衍生物– 4-氨基-3-（N-邻苯二甲酰亚胺基甲基）-1,2,4-三唑-5-硫酮（Tz-1）和3- （N-邻苯二甲酰亚胺甲基）-4-（4-吡啶）氨基-1,2,4-三唑-5-硫酮（Tz-2）在1 M HCl中对低碳钢（MS）表面的腐蚀抑制性能。在添加化合物浓度之前和之后，进行了电化学实验，用于腐蚀的MS表面的电位动力学极化（PDP）和阻抗谱（EIS）测量。加入化合物后PDP反应和相关参数的变化证实Tz-1和Tz-2均为混合型抑制剂。在EIS研究中，随着抑制剂浓度的增加，电容环的直径增加，表明在MS表面形成了吸附层。因此通过控制电荷转移过程来保护腐蚀反应。从PDP和EIS获得的数据相当吻合。两种Tz化合物的IE％（抑制效率）都随着抑制剂浓度的增加而呈上升趋势，并且在最佳浓度2.5×10时，其评估值分别高达95％和94％。^−4M。使用Langmuir模型进行的吸附研究进一步证实了在两种化合物均存在下MS的物理吸附过程。理论DFT（密度泛函理论）分析结果支持了相对更高的Tz-1抑制效率。SEM（扫描电子显微镜）研究表明，在存在Tz-1的情况下，MS表面具有更强的抗腐蚀性能。