共查询到17条相似文献,搜索用时 93 毫秒
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采用丝束电极测试、耦合电流测试、电化学阻抗谱测试等电化学方法,结合表面形貌分析技术,研究了模拟油田采出液中铁氧化菌(IOB)对CaCO3+SiO2沉积层覆盖金属与裸金属之间电偶腐蚀行为的影响。结果表明,IOB增强了沉积层覆盖金属与裸金属之间的电偶效应。在丝束电极测试中,浸泡前6 d内IOB体系的峰值电流密度小于无菌体系,但随着浸泡时间的延长出现反转。电化学阻抗谱测试表明沉积层覆盖金属作为阳极,其表面保护层较为疏松,而裸金属作为阴极,其表面保护层较为致密。IOB促进了沉积层覆盖金属的局部腐蚀,抑制了裸金属的局部腐蚀。 相似文献
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本文采用旋转冲刷实验装置研究945钢在含泥沙海水中的冲刷腐蚀性能,测试介质为青岛附近海域天然海水并加入不同含量的石英砂模拟海水泥沙,分别采用电化学方法检测材料的抗冲刷腐蚀性能、失重法测量腐蚀速率、扫描电子显微镜(SEM)表征金属表面腐蚀产物形貌,并采用X射线衍射仪(XRD)、电子能谱仪(EDS)分析腐蚀产物成分。结果表明,含砂量0.3wt%条件下945钢的阻抗最大,冲刷腐蚀作用最低,随含砂量由0.15wt%增加到1.0wt%,腐蚀产物中的SiO_2含量逐渐增加。当海水流速由1 m/s增大到5 m/s时,945钢的阻抗逐渐减小,腐蚀情况愈加严重,腐蚀产物成分主要为FeO(OH)。 相似文献
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Numerical analysis of galvanic corrosion of Zn/Fe interface beneath a thin electrolyte 总被引:1,自引:0,他引:1
Jong-Min Lee 《Electrochimica acta》2006,51(16):3256-3260
A numerical analysis of galvanic corrosion of a Zn/Fe interface beneath a thin layer electrolyte is presented. Specifically, a circular defect, where the zinc coating has been removed, is considered. It is assumed that both oxygen reduction and iron oxidation can occur on the Fe surface, while only zinc oxidation occurs on the Zn surface. The importance of electrolyte thickness and conductivity and defect radius is considered. It is assumed that the iron and zinc oxidation rates are described by a Tafel relationship. If the kinetic parameters of the oxidation reactions are known, the cathodic protection of Fe is a function of a Wagner number, the ratio of the electrolyte thickness to the defect radius, and the ratio of the radius of the defect to the outer radius of the zinc layer. 相似文献
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The spatial distribution of Zn2+ during galvanic corrosion of a model Zn/steel couple in 0.01 M NaCl was investigated using a scanning zinc disk electrode. The couple had a coplanar arrangement of a steel substrate with an electroplated zinc layer at the center. During galvanic corrosion, the marked changes in the Zn2+ concentration were confined to a thin solution layer ca. 1.0 mm thick above the couple surface. In this thin solution layer above the zinc layer, a higher concentration region of Zn2+ in the range of 5-18 mM extended around the zinc layer in the solution during galvanic corrosion. Conversely, above the steel surface distant from the zinc layer, the surface concentration of Zn2+ was almost zero during galvanic corrosion. On this surface, the precipitation of zinc corrosion products due to the hydrolysis reaction of Zn2+ was observed. The distribution of the Zn2+ concentration supported that Zn2+ acted as a buffer that suppressed the increased pH due to the cathodic reaction on the steel surface near the zinc layer and almost no corrosion products formed there. The spatial distribution of Zn2+ is discussed in relation to the distributions of potential and pH and the surface morphology of the galvanic couple. 相似文献
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应用EFM技术检测碳钢在海水中的腐蚀行为 总被引:2,自引:1,他引:1
电化学频率调制(electrochemical frequency modulation,EFM)是一种腐蚀速度检测的新方法,能够同时测得腐蚀电流密度和Tafel常数。本文以恒电位仪、笔记本电脑、数据采集卡和LabVIEW开发的应用程序建立了EFM测试系统,将其用于低碳钢/海水体系,研究了扰动频率等测试参数对EFM测试结果的影响。在实验室应用EFM方法检测了Q235钢在NaCl溶液和舟山海水中的早期腐蚀速度,并与其他电化学方法进行了比较。结果表明,在低碳钢/海水体系中EFM方法测得的腐蚀速度因界面电容行为的影响而偏大,但EFM技术和测试系统仍然可以作为海洋腐蚀现场检测的一种理想选择。 相似文献
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