X70钢在模拟酸雨溶液中及其液膜下的腐蚀行为研究

采用交流阻抗法和极化曲线法研究了X70钢在模拟酸雨溶液中及其薄层液膜下的腐蚀行为.研究结果表明:在pH值为2.40³.50的模拟酸雨溶液中,X70钢的阻抗谱表现为一个时间常数,X70钢的腐蚀受电荷传递过程控制.X70钢的腐蚀速率和腐蚀电位随着溶液pH值升高而降低.在薄层液膜下,液膜厚度的减薄抑制了腐蚀的阴、阳极过程.液膜厚度的减薄,电荷传递电阻增大,X70钢的腐蚀速率降低.

Corrosion Study of X70 Steel in Simulated Acid Rain Solution and under Thin Electrolyte Layers Formed by Simulated Acid Rain Solution

The corrosion behaviors of X70 steel in simulated acid rain solution and under thin electrolyte layers were studied by polarization curves and electrochemical impedance. It was found that the impedance diagrams of X70 steel in simulated acid rain solution with pH values 2.40-3.50 had one time constant. The control step for corrosion of X70 steel was charge transfer process. The corrosion of X70 steel decreased with the increasing of the pH values. Under thin electrolyte layers, the cathodic and anodic processes were inhabited. The charge transfer increased and the corrosion rate of X70 steel decreased with decreasing the thickness of electrolyte layers.