Bahremand Farshad, Shahrabi Taghi, Ramezanzadeh Bahram, Hosseini Seyed Ali
Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran, Iran.
Department of Surface Coatings and Corrosion, Institute for Color Science and Technology, Tehran, Iran.
Sci Rep. 2023 Jul 27;13(1):12169. doi: 10.1038/s41598-023-38540-9.
One application of organic compounds is to utilize them as corrosion inhibitors in acidic environments to diminish steel corrosion. These inhibitors do not show very good inhibition properties in saline (NaCl) environments. There have been many studies on boosting these inhibitors' performance in such environments (especially Cl containing media). One of the ways that have been proposed is the use of organic and inorganic inhibitors, simultaneously. The synergistic effect of these inhibitors has shown promising results in reducing steel corrosion. In this study, cerium(III) nitrate and tri-sodium phosphate (TSP) was used as organic and inorganic inhibitors to control the corrosion of steel in a 3.5 wt.% NaCl environment. The corrosion measurements were conducted in the 3.5 wt.% NaCl environment by EIS and polarization methods. Surface studies were done by SEM, Raman, GIXRD, and EDS methods. Corrosion studies (EIS and polarization) have revealed that when 500 ppm of Ce(NO) and 500 ppm of TSP are added to the 3.5 wt.% NaCl medium, the highest synergism index (1.27) and inhibition efficiency (73.7%) are achieved. Also, by adding 500Ce-500TPS to the solution, i and R of steel decreased by about 80% and increased approximately 4-fold, respectively. This improvement in the steel performance against corrosion in the presence of an equal ratio of Ce(NO) and TSP is the outcome of the formation of a hydrophobic dense film (consisting of Ce(OH), Ce/Fe-phosphate complexes) on the metal surface. This claim has been proven by SEM/EDS, contact angel, FT-IR, and XRD analysis.
有机化合物的一个应用是将它们用作酸性环境中的缓蚀剂，以减少钢铁腐蚀。这些缓蚀剂在盐水（NaCl）环境中表现出不太好的缓蚀性能。已经有许多关于提高这些缓蚀剂在这种环境（特别是含Cl介质）中性能的研究。提出的方法之一是同时使用有机和无机缓蚀剂。这些缓蚀剂的协同效应在减少钢铁腐蚀方面已显示出有希望的结果。在本研究中，硝酸铈（III）和磷酸三钠（TSP）被用作有机和无机缓蚀剂，以控制3.5 wt.% NaCl环境中钢铁的腐蚀。通过电化学阻抗谱（EIS）和极化方法在3.5 wt.% NaCl环境中进行腐蚀测量。通过扫描电子显微镜（SEM）、拉曼光谱、掠入射X射线衍射（GIXRD）和能谱分析（EDS）方法进行表面研究。腐蚀研究（EIS和极化）表明，当向3.5 wt.% NaCl介质中添加500 ppm的Ce(NO₃)₃和500 ppm的TSP时，可实现最高的协同指数（1.27）和缓蚀效率（73.7%）。此外，通过向溶液中添加500Ce - 500TPS，钢铁的i和R分别降低了约80%和增加了约4倍。在存在等比例的Ce(NO₃)₃和TSP的情况下，钢铁抗腐蚀性能的这种改善是在金属表面形成疏水致密膜（由Ce(OH)₃、Ce/Fe - 磷酸盐络合物组成）的结果。这一说法已通过SEM/EDS、接触角、傅里叶变换红外光谱（FT - IR）和X射线衍射（XRD）分析得到证实。
