Cu-P-RE耐大气腐蚀钢的耐点蚀性能研究

Pitting Corrosion Resistance of Cu-P-RE Weathering Resisting Steel

通过电子探针、扫描电镜和能谱仪等物理手段和极化实验、交流阻抗等电化学方法研究了稀土耐候钢的耐点蚀性能。结果表明,稀土元素的加入提高了耐候钢的点蚀电位。普通Cu-P耐候钢的耐点蚀性和点蚀形貌与普碳钢相接近。耐候钢加入稀土后,稀土元素能使钢中长条状硫化锰或尖角链状的硅酸盐等有害夹杂物变质为细小球形的稀土夹杂,从而降低钢的点蚀敏感性,提高了钢的耐点蚀能力。且球状稀土夹杂物诱发的点蚀坑更加细小均匀,有利于腐蚀后期致密锈层的生成,能提高钢的耐蚀性。

The pitting corrosion resistance of Cu-P-RE weathering steels was investigated by using physical means including electron probe microanalysis （EPMA） scanning electron microscope （SEM） and EDS and electrochemical tests including potentiodynamic polarization curves and electrochemical impedance spectroscopy （EIS）. The results show that the addition of rare earth can improve the pitting potential of weathering steel. The pitting corrosion resistance and pitting morphology of ordinary Cu-P weathering steel is closed to carbon steel. The rare earth elements can modify the strip manganese sulfide or sharp chain silicate inclusions to small global rare earth inclusions, which can reduce the sensitivity of pitting corrosion and improve the pitting corrosion resistance of Cu-P weathering steel. Pitting holes induced by spherical rare earth inclusions of RE weathering steel are more small and uniform, which is beneficial to the formation of compact rust layer in the later corrosion period. So the corrosion resistance of the weathering steel improves.