氧化皮对SS400热轧带钢耐蚀性的影响

EFFECTS OF OXIDE SCALE ON CORROSION PERFORMANCE OF SS400 HOT ROLLED STRIP

通过热处理在SS400热轧带钢表面生成氧化皮,采用SEM、XRD和EDS等手段观察分析了氧化皮的组成及结构。结合极化曲线、电化学阻抗谱(EIS)及扫描Kelvin探针(SKP)测试,探讨了SS400热轧带钢表面氧化皮状态与其耐蚀性能之间的关系。结果表明,连续、致密和完整的氧化皮能减缓腐蚀的进行,起到保护钢基体的作用;随着腐蚀时间的增加,腐蚀电池的阴极区和阳极区的电位差增大,腐蚀加速进行,阴极区和阳极区趋于明显,且呈现局部腐蚀的特征,氧化皮对金属基体的保护作用减弱。

SEM,XRD and EDS were used to observe and analyze the structure and phase composition of the oxide scale on the SS400 hot rolled strip steel prepared by heat treatment in the laboratory.Electrochemical polarization,electrochemical impedance spectroscopy（EIS） and scanning Kelvin probing（SKP） were also used to reveal the relationship between the state of the oxide scale of hot rolled strip and its corrosion behavior.The results showed that the continuous,compact and integrated oxide scale could retard the general corrosion rate and protect steel substrate.With corrosion time increasing,the potential difference between the cathodic and anodic areas in corrosion cell increased,so the strip corroded more quickly,accompanied with the appearance of the distinct characters of localized corrosion and the cathodic and anodic areas separated from each other evidently.Therefore,the protective effect of the oxide scale to the base metal was weakened.