For studying the effect of cathode/anode alternating polarization on the corrosion of Q235 carbon steel, the corrosion behaviors under four states(±50 mV, ±100 mV, ±150 mV and ±200 mV)were studied by square-wave cathode/anode alternating polarization, and the results of weight loss and electrochemical tests were obtained.Results showed that the cathode/anode alternating polarization would accelerate the corrosion of Q235 steel in seawater, and the greater the amplitude of the cathode/anode alternating polarization, the stronger the acceleration effect.After the cathode/anode alternating polarization for different times to Q235 steel, the current density presented the process of “momentary rise-rapid decrease-stabilization after 500 s” when +50 mV, +100 mV and +150 mV anode polarization were applied.In comparison, the current density showed the process of “momentary rise-rapid decrease-continuously increase” when +200 mV anode polarization was applied.Moreover, the AC impedance results indicated that the Rct (charge transfer resistance)value of Q235 steel after undergoing cathode/anode alternating polarization was less than that of the immersion condition, and the greater the amplitude of the alternate polarization, the smaller the Rct value.The result of the polarization curve showed that when the cathode/anode alternating polarization exceeded more than ±100 mV, the cathode process of Q235 steel corrosion accelerated significantly.
