In order to study the Frumkin correction effect of corrosion electric field generated by 921A-B10 galvanic couple in different concentrations of NaCl solution, the electric double layer (EDL) capacitance of 921A steel and B10 copper alloy at the galvanic potential was acquired by electrochemical impedance spectroscopy (EIS), which was calculated for the experimental value of diffuse layer potential. The theoretical value of diffuse layer potential was got by the theoretical relationship between the diffuse layer potential and the total potentia...