Electrochemical Study of the X70 Steel Corrosion Under Thin Electrolyte of NaCl

The corrosion of X70 steel under thin electrolyte layers was studied in NaCl by polarization curves and EIS.It was found that in bulk solution with the increasing of Cl-,the anodic reaction was promoted,the charge transfer resistance and the corrosion potential decreased,the corrosion rate increased.When the concentration of Cl-was more than 0.20mol/L,the corrosion rate of X70 steel decreased.Under thin electrolyte layers,in the range of 1000μm to 120 μm,the cathodic diffusion limiting current was nearly a constant.The further decreased in the electrolyte layer thickness increased the cathodic diffusion limiting current sharply.The corrosion rate of X70 steel increased firstly and then decreased with the decreasing of the electrolyte layer thickness.