酸性土壤中的模拟滞留液溶液对X80钢腐蚀行为的影响

Effect of Simulated Trapped Solution on Corrosion of X80 Steel in Acidic Soil Environment

采用矩形剥离缝隙模型,原位测量了酸性鹰潭土壤模拟溶液中的剥离区滞留液的成分变化,选配了剥离体系腐蚀前期和后期的模拟滞留液溶液,并通过动电位极化曲线、电化学阻抗谱和微观形貌分析对其腐蚀性进行评价。结果表明,剥离体系腐蚀后期滞留液的Cl-,Na+,K+含量升高,溶解氧含量减少、pH降低,其腐蚀电流密度升高,电荷转移电阻Rct减小,保护性腐蚀产物膜受到破坏,点蚀程度明显加重。相较本体溶液和前期滞留液,后期滞留液的腐性更严重。

The changes in the nature of trapped solution in Yingtan acid soil simulation solution were in-situ measured with rectangular disbonded model, and the simulated trapped solution of early and late corrosion were matched. The properties of the solutions were analyzed by potentiodynamic polarization curves, electrochemical impedance spectroscopy, and micro-morphology. The results showed that the contents of Cl-, Na＋ and K＋ increased, the dissolved oxygen content and pH reduced at the late stage of disboned corrosion. At the same time, the corrosion current density increased, the charge transfer resistance （Rct） decreased, the protective corrosion product films were destroyed seriously, and pitting extent increased significantly. Compared with the bulk solution and early corrosion solution, the trapped solution was more aggresive.