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

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.