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为了考察新型海洋平台用E690钢在海水环境中的耐蚀性能,采用动电位极化曲线、电偶电流测量以及扫描电镜和拉曼光谱分析法研究了其在溶氧量为0.3-8 mg/L之间的3.5%NaCl溶液中的氧浓差腐蚀行为,并讨论了溶氧量差值、阴阳极面积比以及锈层等因素对E690钢氧浓差腐蚀的影响。结果表明:当阴阳极面积比Sc/a≤4时,阴阳极面积比是影响氧浓差腐蚀的主要因素,当Sc/a>4,阴极区溶氧量是影响氧浓差腐蚀的主要因素;锈层氧浓差腐蚀的影响与所处的环境有关,处于贫氧条件下时,对锈层下的金属有保护作用,而处于富氧氧条件下,锈层会参与阴极反应,加速金属腐蚀,并且由于锈层的不均匀性,还会造成阳极金属的不均匀腐蚀,产生点蚀坑。
In order to investigate the corrosion resistance of E690 steel in seawater environment for a new type of offshore platform, the kinetic potentiodynamic polarization curve, galvanic current measurement, scanning electron microscopy and Raman spectroscopy were used to study the corrosion resistance of E690 steel in seawater environment. L and between 3.5% NaCl solution. The effects of different dissolved oxygen, anode-anode area ratio and rust layer on the oxygen concentration corrosion of E690 steel were discussed. The results showed that the area ratio of cathode to anode was the main factor affecting the corrosion of oxygen concentration when the ratio of anode to cathode was Sc / a≤4. When Sc / a> 4, the dissolved oxygen in cathode area was the main factor affecting the corrosion of oxygen concentration ; Rust layer oxygen concentration corrosion related to the impact of the environment, in oxygen-poor conditions, the metal under the rust layer has a protective effect, and in the oxygen-rich conditions, the rust layer will participate in the cathode reaction to accelerate the metal Corrosion, and due to the heterogeneity of the rust layer, it also causes nonuniform corrosion of the anode metal and pitting corrosion pits.