Corrosion inhibition effect of 2-Hydroxy Phosphonoacetic Acid and Pyrophosfate on Q235 steel, Electrochemical Noise and EIS analysis

The inhibiting behavior of K4P2O7, C2H5O6P and their mixture on Q235 steel corroding in the simulated stratum water has been investigated by using electrochemical noise (EN) and electrochemical impedance spectroscopy (EIS) techniques. The results show that the physical adsorption of KPP onto Q235 surface at 60 °C is somewhat faster than the chemisorption of HPAA. In the re-plotted energy distribution plot, the difference of the region where the EN energy is mostly accumulated may be adopted to distinguish the chemisorption and physical adsorption of inhibitors. Finally, the variation tendency of the charge transfer resistance obtained by EIS technique is just opposite to that of fractal dimension obtained by EN technique, which may hint that the initial corrosion processes of metals can be in-situ monitored by using EN technique expediently.