925镍基合金和110SS钢在高温高酸性环境中的电偶腐蚀行为

目的 探究镍基合金925和抗硫油管管材110SS在不同面积比下耦接后的电偶腐蚀行为和电偶腐蚀效应，模拟国内某油气田高温高酸性腐蚀环境。方法 采用浸泡腐蚀试验和电化学测试技术，评价电偶腐蚀的阴阳极过程对腐蚀进程的影响，并利用扫描电子显微镜(SEM)、X射线能谱仪(EDS)与X射线衍射仪(XRD)对腐蚀试样的表面形貌及腐蚀产物成分进行分析。结果 110SS的自腐蚀电位远远低于925，阴阳极分别以1:1、1:5、1:10、1:30四种面积比耦接后，均发生电偶腐蚀。耦接后110SS的腐蚀速率分别为:0.7564、0.7032、0.6457、0.6289 mm/a，均为极严重腐蚀。结论 电偶腐蚀速率和电偶腐蚀效应均随着阴阳极面积比的增大而增加。镍基合金与碳钢油管耦接主要对材料在腐蚀环境下的腐蚀进程有影响，而对腐蚀产物和腐蚀机理的影响不大。

Galvanic Corrosion Behavior of Nickel-based Alloy 925 for Downhole Tools Coupled With 110SS Steel

To investigate the galvanic corrosion behavior and galvanic effect between nickel-based alloy 925 for downhole tools and sulfur resistant pipeline 110SS steel in different area ratios, a High temperature and high sour environment was simulated in oil and gas field in China. Electrochemical tests and immersion corrosion tests were conducted in a high temperature and high pressure autoclave, and the corrosion products formed on the metal surface were analyzed by scanning electron microscopy (SEM) and energy disperse spectroscopy (EDS), The results indicate that the free corrosion potential of 110SS steel is much lower than that of nickel alloy 925, even after coupling, galvanic corrosion occurs. The galvanic corrosion rate is positively correlated with the ratio of anode and cathode. While the coupling of heterogeneous metals has no obvious effect on the corrosion products and corrosion mechanism.