Optimal Cathodic Protection Potential for X70 Steel with AC Interference Determined by Electrochemical Methods

Electrochemical methods were used to measure the polarization curves of X70 steel under different alternating stray current (AC)voltage conditions and the electrochemical impedance spectroscopy(EIS) under different cathodic polarization potential conditions.The scope of cathodic protection potential and the optimum cathodic protection potential were determined.The results showed that the use of polarization curves and electrochemical impedance spectroscopy could measure the cathodic protection parameters of X70 steel under different AC voltage conditions,and the optimum cathodic protection potential was suggested to be -900 mV(vs.SCE) at the voltage less than 6 V and -1000 mV(vs.SCE) at the voltage greater than 7V.