模拟酸雨大气环境中Cl-浓度对镀锌钢腐蚀行为的影响

摘要

目的：研究模拟酸雨环境中Cl-浓度对镀锌钢腐蚀行为的影响与作用机理。方法以pH为3.05的模拟酸雨溶液作为空白溶液，在每升空白溶液中分别加入0.01，0.1和0.5 mol的NaCl，浸泡3天和7天后取出试样，进行形貌、成分分析以及电化学分析。结果浸泡后镀锌钢表面形成的腐蚀产物主要为NaZn4SO4Cl（OH）6·6H2O。随着溶液中Cl-浓度的增加，镀锌钢的腐蚀电位逐渐减小，腐蚀电流密度逐渐增大，阻抗值逐渐减小。结论通过不同时间的浸泡，随着溶液中Cl-浓度的增加，镀锌钢表面腐蚀产物对基体都有一定的保护作用，但保护作用逐渐减小，尤其在浸泡3天时的变化最明显。%ABSTRACT:Objective To study the effects of Cl- Concentration on Corrosion Behavior of Hot-dip Galvanized Steel in simulated acid rain atmospheric environment. Methods The simulated acid rain solution (pH=3.05) was used as basic solution, then 0.01, 0.1, and 0.5 mol/L NaCl was respectively added. Samples were immersed in these solution and taken out respectively after 3 days and 7 days. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical techniques were used to analyze the corroded samples. Results After immersion, the corrosion productcomponent that formed on the surface of hot-dip galvanized steel is NaZn4SO4Cl(OH)6·6H2O. Along with the increase of the Cl- concentration, the corrosion potential of the galvanized steel was gradually decreased, the corrosion current was gradually increased and the impedance value was decreased. Conclusion With the increase of Cl-concentration, the protective effects of corrosion product formed on the surface of hot-dip galvanized steel was gradually reduced, especially after 3 days′immersion.