硫酸溶液中铁在过钝化区电极行为

本文应用电位衰减和交流阻抗等电化学方法对H_2SO_4溶液中处于过钝化区的铁的钝化膜的性质进行了研究。发现在钝化-过钝化过渡区域,钝化膜的厚度随着电位的升高而下降。当电位升到1800mV(VS·SCE)以后,钝化膜的厚度不再随电位的变化而变化。对不同电位下的交流阻抗频谱图进行了拟合分析,得到了一些与钝化膜的性质有关的参数。

ELECTROCHEMICAL BEHAVIOUR OF IRON IN THE TRANSPASSIVE REGION IN 0.5mol/L SULPHATE SOLUTION

The electrochemical behavior of the anodic passive film on iron in sulphuric acid in the transpassive region has been studied by electrochemical techniques. The duration of potential decay indicated that the film formed in the passive region become thicker with the increase of the electrode potential, in contrast, the thickness of the film formed in the transpassive region decreased as the electrode potential increased , and it is also found that the film thickness remained nearly constant above the potential of 1800mV. Also, the impedance spectra of iron were measured at different potentials. The difference between the spectra of passive layer and that of transpassive layer was shown. By fitting the impedance spectra, some parameters and information concerning the film formed in transpassive region were obtained.