316L不锈钢在不同浓度Cl^(-)和CO_(2)条件下的腐蚀行为

Corrosion Behavior of 316L Stainless Steel under Different Concentrations of Cl^(-)and CO_(2) Conditions

为了探明在辽河油田采出水环境中Cl^(-)和CO_(2)对316L不锈钢腐蚀行为的影响,通过浸泡实验、交流阻抗(EIS)和极化曲线技术分别研究了不同Cl^(-)浓度和CO_(2)分压对316L不锈钢的影响,其中Cl^(-)浓度梯度为0,0.0300,0.0515,0.0700 mol/L,CO_(2)分压为0.2,0.4,0.6 MPa,并结合X射线衍射技术(XRD)对腐蚀产物进行了分析。结果表明:Cl^(-)浓度的增大使容抗弧直径减小,弥散指数降低,腐蚀情况加剧;容抗弧的直径随着CO_(2)分压的增大先变小后变大,弥散指数先降低后升高,腐蚀情况先加剧后减缓。这是由于Cl^(-)会破坏316L表面的钝化膜,而CO_(2)会与基体反应生成FeCO_(3),随着CO_(2)分压升高,FeCO_(3)保护膜愈加致密。

In order to elucidate the impact of Cl^(-)and CO_(2) on the corrosion behavior of 316L stainless steel in the produced water environment of the Liaohe oilfield,the effects of varying Cl^(-)concentrations and CO_(2) partial pressures on 316L stainless steel were investigated through im-mersion tests,electrochemical impedance spectroscopy(EIS)and polarization curve techniques.The Cl^(-)concentration gradients were 0,0.0300,0.0515,0.0700 mol/L,while the CO_(2) partial pressures were set at 0.2,0.4,0.6 MPa.Additionally,X-ray diffraction(XRD)technology was employed to analyze the corrosion products.Results showed that with the increase of Cl^(-)concentration,the diameter of the capacitive reactance arc decreased,the dispersion index decreased,and the corrosion was intensified.With the increase of CO_(2) partial pres-sure,the diameter of the capacitive reactance arc first decreased and then increased,the dispersion index first decreased and then increased,and the corrosion first intensified and then slowed down.This was due to the fact that Cl^(-)would destroy the passive film on the surface of 316L,while CO_(2) would react with the substrate to form FeCO_(3).With the increase of CO_(2) partial pressure,the FeCO_(3) protective film became denser.