温度对X70钢在高pH值溶液中腐蚀行为的影响

Effect of temperature on corrosion behavior of X70 pipeline steel in high pH solution (0.5 mol/L Na2CO3+0.5 mol/L NaHCO3) was studied by means of potentiodynamic polarization, electrochemical impedance spectroscopy and Mott- Schottky measurements. Results showed that the pitting potential, passive current density and the polarization resistance of X70 pipeline steel all decreased with the increase of temperature. In the experimental temperature range, the formed passive film consisted mainly of Fe2O3 and Fe3O4 with features of n-type semiconductor. With the rising temperature, the thickness and donor density of the passive film increased, correspondingly, corrosion tendency of the steel increased. Therefore, the stability of the passive film decreased with the increasing temperature, which weakened the corrosion resistance of the X70 steel.