Cu-P-RE耐候钢的耐蚀性能

Corrosion resistance of Cu-P-RE weathering steel

通过干湿周浸加速腐蚀实验研究了不同稀土含量的耐候钢和对比普碳钢的腐蚀行为及其耐蚀性能.采用失重法测得了各试样的腐蚀率;结果发现,稀土耐候钢的腐蚀率远远低于普碳钢的,不同稀土含量的耐候钢的耐腐蚀性不尽相同.采用电化学交流阻抗技术对带锈钢样的表面锈层结构及电化学反应过程进行了研究,提出在本实验条件下钢电化学腐蚀的等效电路模型,计算出锈层电阻、极化阻抗等表征锈层性能的电化学元件参数值.稀土耐候钢锈层中存在半无限扩散和有限厚度扩散两种过程,有限厚度扩散极化阻抗反映了耐候钢内锈层的保护性能.

The corrosion behavior and corrosion resistance of Cu-P-RE weathering steel and plain carbon steel were studied by drywet cycle immersion test. A weight-loss method was used to measure the corrosion rates of all steel samples. The results show the corrosion rate of Cu-P-RE weathering steel is much lower than that of 0.235 steel. The corrosion resistances of the weathering steels with different rare earth contents are distinguishing. The structure of rust layer on the rusty steel samples and its electrochemical reaction process were investigated by electrochemical impedance spectra techniques. An equivalent circuit was set up to represent the steel/ solution interface reaction. Some electrochemical parameters such as rust layer resistance and polarization impedance were deduced from electrochemical impedance spectra of the steels. The parameters can estimate the protective properties of rust layer. There are two different diffusion processes, which are semi-infinite diffusion and finite thickness diffusion, in rust layer on the RE weathering steel. The protective properties of inner rust layer on the weathering steel can be estimated by the polarization impedance of finite thickness diffusion.