CO2和H2S对FV520B不锈钢在NaCl溶液中电化学腐蚀行为的影响

Effects of CO2 and H2S on Electrochemical Corrosion Behavior of FV520B Stainless Steel in NaCl Solution

采用动电位极化和电化学阻抗谱研究了FV520B不锈钢在3.5%(质量分数,下同)NaCl溶液以及在分别通入CO2、H2S、CO2+H2S气体的3.5%NaCl溶液中的电化学腐蚀行为。结果表明:在3.5%NaCl溶液中通入CO2或H2S时,试验钢的开路电位负移,极化电阻减小,耐腐蚀性能变差;试验钢在4种腐蚀介质中的极化曲线均呈阳极溶解特征,在3.5%NaCl和通入CO2的3.5%NaCl溶液中,腐蚀受阳极过程控制,在通入H2S的3.5%NaCl溶液中,腐蚀受阴极过程控制,而在同时通入CO2和H2S的3.5%NaCl溶液中,腐蚀受阴极和阳极过程共同控制。

Electrochemical corrosion behavior of FV520B stainless steel in 3.5wt%NaCl solution and in 3.5wt%NaCl solutions containing CO2,H2S and CO2+H2S,respectively,was studied by potentiodynamic polarization and electrochemical impedance spectroscopy.The results show that the open circuit potential of the test steel shifted to the negative direction,the polarization resistance decreased and the corrosion resistance became worse.The polarization curves of the test steel in four corrosive media showed anodic dissolution characteristics.In the 3.5wt%NaCl and 3.5wt%NaCl+CO2 solutions,the corrosion was dominated by anodic reaction;in the 3.5wt%NaCl+H2S solution,the corrosion was dominated by cathodic reaction;the corrosion was dominated by the anodic and cathodic reaction when H2S and CO2 coexisted in the 3.5wt%NaCl solution.