铬污染对Q345钢在抚顺污灌区土壤腐蚀行为的影响

Effect of Chromium Contamination Corrosion Behavior on Q345 Steel in Soil of Sewage Water Irrigation Region in Fushun

利用腐蚀速率失重法、扫描电镜(SEM)、能谱(EDS)以及电化学测试技术,研究了Q345钢在被重金属铬污染土壤溶液中的腐蚀行为。研究表明:Q345钢在原状土壤溶液中浸泡2周后的腐蚀程度明显比在铬污染的土壤溶液中严重,试样整个表面被腐蚀产物覆盖,而在铬污染的土壤中其表面光亮可鉴;去除腐蚀产物后观察试样的微观形貌发现,试样在原状土壤中为全面腐蚀,而在铬污染的土壤中部分区域出现点蚀坑。电化学测试结果表明:电荷转移电阻和自腐蚀电流密度均随铬质量分数的增加而逐渐降低。这说明试样在铬污染土壤中其表面形成了一层钝化膜,对基体起到保护作用,从而减缓Q345钢的土壤腐蚀。

The corrosion behavior of Q345 steel in soil solution which has been polluted with chromium was studied by mass measurement, scanning electron microscopy（SEM）, energy disperse spectrum（EDS） and electrochemical techniques. It is shown by the results after two week＇s immersing that the Q345 steel in undisturbed soil solution is more serious than that in the soil of chromium pollution, which is covered by corrosion products. But the surface of steel in the chromium contaminated soil is smooth. It is observed after rust cleaning that the corrosion type of steel in undisturbed soil is general corrosion, but the surface of steel in chromium contaminated soil partly generates pitting. The electrochemical test shows that the charge-transfer resistance and corrosion current density gradually reduces with the increase of mass fraction chromium. This illustrates that a layer of passivation film is formed on the surface of the steel in chromium contaminated soil, which produces an effect of protection on the matrix and slows the corrosion of Q345 steel.