X80管线钢红壤腐蚀初期电化学行为

Electrochemical Behavior of X80 Pipeline Steel in the Initial Stage of Corrosion in an Acidic Red Soil

通过室内土壤埋样实验，采用电化学阻抗谱（EIS）和极化技术研究了X80管线钢在红壤泥浆中的早期腐蚀行为。结果表明，X80管线钢在水饱和红壤中腐蚀初期（15d内）的EIS具有两个时间常数特征，高频端呈现土壤介质特征容抗弧，10^-2～10^4Hz频区为腐蚀界面反应过程对应的容抗弧，低频区（〈10^-2）为点蚀形核期产生的感抗弧；腐蚀30d后电极反应过程受扩散过程控制。提出了红壤对管线钢的高腐蚀性与红壤铁氧化物间的关联。

Corrosion of X80 pipeline steel in an acidic red soil slurry was studied by means of electrochemical impedance spectroscopy （EIS） and polarization technique. The results show that in a water-saturated red soil, the EIS of X80 steel contains a capacitive arc at high frequency and a capacitive arc from the interface process in frequency region of 10^-2-10^4 Hz as well as an inductive loop appears at low frequency exhibiting processes related with adsorption or pitting nucleation; the electrode process was controlled by diffusion process after 30 d exposure; iron oxides residing in the soil tend to enhance the corrosion process of the steel, correspondingly a corrosion mechanism has been proposed.