模拟酸雨大气环境中Cl^-浓度对镀锌钢腐蚀行为的影响

Effects of Cl^- Concentration on Corrosion Behavior of Hot-dip Galvanized Steel in Simulated Acid Rain Atmospheric Environment

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p H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Na Cl,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Na Zn4SO4Cl(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。

Objective To study the effects of C1- 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 NaC1 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 product component that formed on the surface of hot-dip galvanized steel is NaZn4SO4CI（OH）6.6H20. Along with the increase of the C1- 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 C1- concentration, the protective effects of corrosion product formed on the surface of hot-dip galvanized steel was gradually reduced, especially after 3 days＇ immersion.