Abstract

An electrochemical study of three API steels: X52, X65, and X80, exposed to seawater and sediment from seabed is presented. Two seabed samples were collected at 60 meters depth near a platform (seabed A) and at a distance of 500 m (seabed B) from the same platform of the Sonda of Campeche, México. In both samples, the seawater and sediment were separated in order to characterize their corrosiveness in an electrochemical cell of 100 mL. The physicochemical and electrochemical responses were determined in the water and sediment. Electrochemical impedance spectra and polarization curves for both water and sediment from the two seabed samples were carried out. A cathodic protection analysis for the three steel surfaces exposed to sediment was proposed based on cathodic polarization curves. Corrosion rates for the three studied low carbon steels could be attributed to their physicochemical properties and low temperatures from a specific seabed area. Thus, high susceptibility to corrosion was identified when three API steels were in contact with seabed B. A corrosive gas fixation and discharges of produced water into the seabed that are able to conduct the corrosion process were suggested. In order to study the activation energies of corrosion for the API steels exposed to sediment, a low temperature dependence was taken into account using the Arrhenius equation and R_ct values from impedance data. Activation energy values were E_a = 23.06, 31.7, and 43.2 J mol^–1 in X52, X80, and X65 steels, respectively.

中文翻译：

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墨西哥湾海底海水和沉积物中三种API钢对外腐蚀的电化学研究

摘要

提出了三种API钢X52，X65和X80的电化学研究，这些钢暴露于海水和海底沉积物中。在平台附近（海床A）60米深处和距离海床B 500 m处采集了两个海床样本。）来自墨西哥坎佩切州Sonda的同一平台。在两个样品中，将海水和沉积物分开以表征其在100 mL电化学池中的腐蚀性。测定了水和沉积物中的物理化学和电化学响应。绘制了两个海床样品中水和沉积物的电化学阻抗谱和极化曲线。基于阴极极化曲线，提出了三个暴露于沉积物的钢表面的阴极保护分析。三种研究的低碳钢的腐蚀速率可归因​​于其理化特性和特定海底区域的低温。因此，当三种API钢与海床B接触时，发现对腐蚀的敏感性很高。。提出了一种腐蚀性气体固定装置，并将能够进行腐蚀过程的产出水排入海床。为了研究暴露在沉积物中的API钢的腐蚀活化能，使用Arrhenius方程和阻抗数据中的R _ct值考虑了低温依赖性。在X52，X80和X65钢中，活化能值分别为E _a = 23.06、31.7和43.2 J mol ^–1。