硫酸中硫脲影响铁腐蚀行为的机制

INFLUENCE OF THIOUREA ON CORROSION BEHAVIOR OF IRON IN H_2SO_4 SOLUTION

用近稳态极化曲线方法和交流阻抗方法研究了铁在硫脲浓度低于０．１ｍｍｏｌ／Ｌ的硫酸溶液中的腐蚀行为，获得了相关的电化学参数。结果表明，在低阳极极化区，铁阳极溶解反应的速率决定步骤是一个亲核加成反应，动力学参数为Ｖ（ＴＵ）＝１，ｂａ≈６０ｍＶ。在阴极区，析氢反应的速率决定步骤是Ｈｅｇｒｏｖｓｋｙ反应，动力学参数为：Ｖ（ＴＵ）＝０．５，Ｖ（Ｈ＋）＝１．５，ｂｃ≈－８２ｍＶ。

The corrosion behavior of iron electrode in H2SO4 containing thioures(C 0.1 mmol/L)was investigated with polarization curves and EIS method.Various electrochemical parameters involved were obtained.The results showed that,the rate determining step(r.d.s)for anodic dissolution reaction of iron in low polarization region was a nucleophilic additive reaction,and the corresponding kinetics parameters were VTU=1,ba≈60mV.The r.d.s for its catbodic process was a Heyrovshky Heyrovsky reaction,and the kinetics parameters were:VTU=-0.5,VH+=1.5,bc≈-82mV.