Abstract

The sour corrosion of C1018 carbon steel in CO₂-saturated 3.5% NaCl + 100 ppm H₂S solution and its inhibition by a low-toxic molecule, 1–benzylimidazole (1–Benz), has been investigated. Electrochemical impedance spectroscopy (EIS) results reveal that 1–Benz can form a strongly-adsorbed and highly protective inhibitor layer on the steel surface. Potentiodynamic polarization (PDP) results confirm that 1–Benz is a mixed–type corrosion inhibitor with slightly more anodic tendency. An optimum concentration of 150 ppm provided up to 83% inhibition efficiency. Based on FTIR characterization, 1–Benz interacts with the steel surface using its nitrogen atom and C=C pi-electrons and it adsorbs following the Temkin isotherm. The adsorption reduces localized corrosion, according to SEM-EDX observations. Theoretical parameters confirm that the electron–rich imidazole N atoms and electron-deficient C atoms in the phenyl ring ensure easy electron transfer between 1–Benz and the steel surface.

摘要

C1018碳钢在CO ₂饱和3.5% NaCl + 100 ppm H _{2中的酸腐蚀}已经研究了 S 溶液及其对低毒分子 1-苄基咪唑 (1-Benz) 的抑制作用。电化学阻抗谱（EIS）结果表明，1-Benz可以在钢表面形成一层强吸附且保护性强的缓蚀层。动电位极化 (PDP) 结果证实 1-Benz 是一种混合型缓蚀剂，具有稍强的阳极倾向。150 ppm 的最佳浓度可提供高达 83% 的抑制效率。基于 FTIR 表征，1-Benz 使用其氮原子和 C=C π 电子与钢表面相互作用，并按照 Temkin 等温线进行吸附。根据 SEM-EDX 观察，吸附减少了局部腐蚀。