Pitting Corrosion of X80 Pipeline Steel in 0.5 mol/L NaHCO₃+0.02 mol/L NaCl Solution

The corrosion behavior of X80 and X70 pipeline steels in 0.5 mol/L NaHCO3+0.02 mol/L NaCl solution was studied by potentiodynamic polarization technique and EIS,and the corrosion mechanism was investigated by capacitance measurements.It was shown that the potential of pitting corrosion for X80 pipeline steel was more noble than that of X70 steel,and the pitting probability was lower for X80 steel.Mott-Schottky results indicated that the value of donor density for passive film formed on X80 steel was less than that on X70 steel,and the potential sites for pitting corrosion initiation were more for X70 steel,so the pitting resistance of X80 steel was better than that of X70.