设计了一种能够模拟垢下局部腐蚀自催化过程的闭塞电池，并用线性极化和电化学阻抗方法研究了闭塞阳极内电化学行为的变化。研究表明：垢层将加剧微区内的酸化自催化作用，pH值降低，Cl-浓集，闭塞区内外产生明显的耦合电流，内部保持活性阳极溶解, 外部受到阴极保护。闭塞微区内阳极溶解受界面电荷传递的电化学过程控制。持续的闭塞效应，使垢层下微区内阳极溶解不断进行，并随偶合时间的延长基体金属界面反应电阻有所降低，阳极反应变得更为容易。
An occluded corrosion cavity (OCC) cell which could simulate the auto-catalyzing process of localized corrosion was designed to study the under scales corrosion behavior of carbon steel in neutral NaCl solution in this paper. Electrochemical impedance spectroscopy (EIS) and linear polarization curves measurements were employed to study the variation of electrochemical behavior within the occluded anode. The result showed that the auto-catalyzing acidification process inside the OCC is exacerbated by corrosion products layer. A galvanic current produced obviously between the occluded anode and bulk cathode, the solution inside the OCC become more acid and the Cl- is centralized, occluded anode kept up activation dissolution, while the bulk cathode outside the OCC was partly or fully protected. The active dissolution in occluded anode is controlled by an irreversible charge transfer process at metal/oxide film interface. The charge transfer resistance and linear polarization resistance decrease with the short-circuited time continually. The occluded anode dissolution reaction was developed persistently by the occluded effect and become easier along with the short-circuited time continually.
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