The cathodic reaction mechanisms in CO₂ corrosion of low-Cr steels were investigated by potentiodynamic polarization and galvanostatic measurements. Distinct but different dominant cathodic reactions were observed at different pH levels. At the higher pH level (pH > ~5), H₂CO₃ reduction was the dominant cathodic reaction. The reaction was under activation control. At the lower pH level (pH < ~3.5), H⁺ reduction became the dominant one and the reaction was under diffusion control. In the intermediate area, there was a transition region leading from one cathodic reaction to another. The measured electrochemical impedance spectrum corresponded to the proposed cathodic reaction mechanisms.

通过恒电位极化和恒电流测量研究了低Cr钢在CO ₂腐蚀中的阴极反应机理。在不同的pH值下观察到截然不同但不同的主要阴极反应。在较高的pH水平（pH>〜5）下，H ₂ CO ₃还原是主要的阴极反应。反应在活化控制下。在较低的pH值（pH <〜3.5）下，H ⁺还原成为主要反应，并且反应在扩散控制下进行。在中间区域，存在一个从一个阴极反应到另一个阴极反应的过渡区域。测得的电化学阻抗谱与所提出的阴极反应机理相对应。