Purpose

The purpose of this paper is to investigate the influence of the potential of hydrogen (pH) and dissolved oxygen in artificial seawater on the passivation behavior of 316L stainless steel.

Design/methodology/approach

The corrosion behavior was studied by using electrochemical measurements such as electrochemical impedance spectroscopy and polarization curve. The passive films were characterized with X-ray photoelectron spectroscopy.

Findings

The polarization resistance of the passive film decreases as the pH value drops ascribed to the formation of much more point defects. The donor carrier concentration (ND) in the passive film formed in the deaerated condition is lower than that in aerated conditions. Nevertheless, this phenomenon is the opposite when the pH value is 1 due to the significant decrease of Fe oxides/hydroxides coupled with the stable content of Cr oxides/hydroxides species. In addition, the compositional variation of the passive film also leads to the changes of its semiconductor properties from N-type to bipolar type.

Originality/value

This paper shows the variation of polarization resistance, corrosion potential, passive film composition and semiconductor properties with the pH value and dissolved oxygen. The results can serve as references to the further study on crevice corrosion of 316L in seawater.

中文翻译：

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316L不锈钢在人造海水中的钝化行为：pH和溶解氧的影响

目的

本文的目的是研究人工海水中氢（pH）和溶解氧的电势对316L不锈钢钝化行为的影响。

设计/方法/方法

通过使用电化学测量，例如电化学阻抗谱和极化曲线，研究了腐蚀行为。用X射线光电子能谱对无源膜进行表征。

发现

随着pH值的下降，无源膜的极化电阻降低，这归因于形成更多的点缺陷。在脱气条件下形成的钝化膜中的供体载流子浓度（ND）低于在通气条件下形成的供体载流子浓度（ND）。然而，当pH值为1时，由于Fe氧化物/氢氧化物的大量减少以及Cr氧化物/氢氧化物种类的稳定含量，这种现象是相反的。另外，无源膜的组成变化也导致其半导体性质从N型变为双极型。

创意/价值

本文显示了极化电阻，腐蚀电位，钝化膜组成和半导体性能随pH值和溶解氧的变化。研究结果可为进一步研究316L在海水中的缝隙腐蚀提供参考。