Background

This paper studies elemental sulfur-induced corrosion of carbon steel in chloride bearing media. The issue is of great importance in industries dealing with sour gas environment and its mechanism is yet not entirely understood.

Methods

The aim of this study was sought using various electrochemical (such as potentiodynamic polarization, linear polarization resistance technique, electrochemical impedance spectroscopy and zero resistance ammeter technique) and non-electrochemical techniques (such as scanning electron microscopy and Raman spectroscopy).

Findings

It was found that reduction of dissolved oxygen is not the main cathodic reaction in the process of the sulfur-induced corrosion. Besides, severe corrosion primarily occurs at near peripheral region of sulfur deposition, leading to formation of a ring of FeS. However, the FeS accumulation reduces the corrosion rate, over the time. In the long term, a galvanic couple is established between the near peripheral and remote regions of the sulfur deposition. Occurrence of the consequent galvanic corrosion could cause severe corrosion at the regions which are far from the sulfur deposition and are not influenced by the sulfur-based species.

中文翻译：

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使用电化学和非电化学技术深入了解含氯化物介质中碳钢的元素硫腐蚀

背景

本文研究了元素硫引起的碳钢在含氯化物介质中的腐蚀。该问题在处理酸性气体环境的行业中非常重要，其机制尚未完全了解。

方法

本研究的目的是使用各种电化学（如动电位极化、线性极化电阻技术、电化学阻抗谱和零电阻电流表技术）和非电化学技术（如扫描电子显微镜和拉曼光谱）来寻求。

发现

发现溶解氧的减少不是硫致腐蚀过程中的主要阴极反应。此外，严重腐蚀主要发生在硫沉积的近周边区域，导致形成 FeS 环。然而，随着时间的推移，FeS 的积累会降低腐蚀速率。从长远来看，在硫沉积的近周边和偏远区域之间建立了电偶。随之发生的电偶腐蚀可能在远离硫沉积且不受硫基物质影响的区域引起严重腐蚀。