Electrochemical Corrosion Behavior of Q235B Carbon Steel in 10%NaCl and H2S Solutions with Different pH

2018 International Conference of Green Buildings and Environmental Management

土木建筑工程;生态环境科学

Xu, Rongrong^1 ; Wang, Beifu^1 ; Nie, Lihong^1 ; Liu, Yang^1

Zhejiang Ocean University, Zhoushan, Zhejiang

316000, China^1

关键词: Acidic dissolution;    Electrochemical corrosion behavior;    Electrochemical impedance spectra;    High-Frequency regions;    Impedance characteristics;    Low frequency regions;    Potentiodynamic polarization curves;    Working electrode;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/186/2/012023/pdf
DOI  :  10.1088/1755-1315/186/2/012023

来源: IOP

【 摘 要 】

The electrochemical corrosion behavior of Q235B carbon steel in 10% NaCl and H2S solutions with different pH was studied by means of electrochemical impedance spectroscopy(EIS) and potentiodynamic polarization curves. The results show that when the pH is less than 3, the corrosion is mainly controlled by the acidic dissolution process of the anode, and the electrochemical impedance spectrum not only has a capacitive arc in the high frequency region, but also exists an inductive arc in the low frequency region; when the pH is in the range of 3.05 to 6.01, the radius of the capacitive arc increases as the pH increases, and Rr also increases, reaching a maximum at a pH of 5.06, which is related to the deposition and coverage of the black sulfide generated on the surface of the working electrode. Rt and Qdl also increase with the increase of pH; when the pH is higher than 7, the surface of the electrode forms oxide film and sulfide, and the potentiodynamic polarization curve gradually shows passivation characteristics with increasing pH. As large as 9.06, three stages of activation, passivation, and over-passivation can be clearly seen in the potentiodynamic polarization curve. Obvious Warburg impedance characteristics can also be seen in the electrochemical impedance spectrum.