H_2S水溶液中的腐蚀与缓蚀作用机理的研究 Ⅶ.H_2S溶液中咪唑啉衍生物对碳钢腐蚀电极过程的影响

STUDY ON CORROSION AND INHIBITION MECHANISM IN H_2S AQUEOUS SOLUTIONS Ⅶ.Effect of Imidazoline Derivates on the Corrosion Process of Mild Steel Electrodes in H 2S Solutions

利用电化学测试技术 ,在H2 S溶液中分别研究了 14种咪唑啉衍生物浓度的变化对其缓蚀性能以及碳钢腐蚀电化学过程的影响 ,并对其缓蚀作用过程、缓蚀类型进行了分析探讨。结果表明 ,随药剂浓度升高 ,体系的自腐蚀电流和电极表面电容迅速减少 ,极化电阻增大 ,表明缓蚀剂分子在电极表面的吸附随药剂浓度的增加而增加 ,屏蔽效应增强 ;咪唑啉分子结构中憎水支链的长短对其缓蚀作用类型有重要影响 ,随支链中碳原子增加 ,化合物的缓蚀作用类型逐渐由阴极型向阳极型转变 ;按其对电极过程作用性质的不同 ,所研究的 14种咪唑啉衍生物可分为阳极型和阴极型缓蚀剂两种 。

Effect of imidazoline derivates on their inhibitive performance and corrosion process of mild steel electrodes with the variation of additional concentration in H 2S solutions was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS),the inhibitive type and mechanism of compounds studied was discussed as well.Results show that with the increasing of additional concentration,the corrosion current density and interfacial capacitance of mild steel electrodes sharply decrease,the polarization resistance increases and inhibition efficiency of the compounds has been enhanced.That demonstrates imidazoline compounds have an effectively inhibition performance because of the strong chemical adsorption of imidazoline molecule on the surface of electrodes.With the increasing of number of carbon atoms in hydrophobic side chain,the type of inhibitor has reversed from anodic inhibitor to cathodic inhibitor,which indicates that the length of hydrophobic side chain plays an important role in the active type and inhibition mechanism of imidazoline derivates.14 compounds studied can be divided into two types,one is anodic inhibitor,another is cathodic inhibitor according to the reactive parameter for the electrode process.