一种高强度多功能建筑结构用钢的耐蚀性及耐蚀机理

Corrosion resistance and its mechanism of a multifunctional high strength construction structural steel

采用周期浸润腐蚀实验研究了一种新型多功能建筑结构用钢在模拟近海洋环境(3.5%NaCl溶液,质量分数)下的腐蚀行为.利用扫描电镜(SEM)、CS 2350电化学工作站、电子探针(EPMA)及X射线衍射仪(XRD)等手段,对不同腐蚀周期后实验钢锈层的形貌、腐蚀产物物相及元素分布和耐蚀机理等进行了研究和分析.结果表明:随着腐蚀周期的增加,实验钢表面形成了稳定的锈层,最终的腐蚀产物主要由保护性的α-FeOOH和Fe_(3)O_(4)组成.钢中Cu,Cr和Ni在内锈层中富集,使实验钢腐蚀产物由初期疏松的β-FeOOH和γ-FeOOH转变为后期致密、稳定且绝缘、非活性的α-FeOOH,与Fe_(3)O_(4)一起稳定存在,增加了锈层致密度,从而增强了钢的耐蚀性能.

The anti-corrosion behavior of a new multifunctional building structural steel in simulated near marine environment(3.5%NaCl solution,mass fraction)was studied by periodic immersion corrosion experiment.By means of scanning electron microscope(SEM),CS 2350 electrochemical workstation,electron microprobe analysis(EPMA)and X-ray diffraction(XRD),the morphology,phase and element distribution of corrosion products and corrosion resistance mechanism of the experimental steel after different cycles of corrosion were studied and analyzed.The results show that with the increase of corrosion cycle,a stable rust layer is formed on the surface of the steel,and the final corrosion products are mainly protectiveα-FeOOH and Fe_(3)O_(4).Due to the enrichment of Cu,Cr and Ni in the inner corrosion layer,the corrosion products of the steel change from looseβ-FeOOH andγ-FeOOH at the initial stage to the dense,stable and insulating inactive productα-FeOOH in the later stage,which exists stably together with Fe_(3)O_(4),increases the density of the corrosion layer,thus enhancing the corrosion resistance of the steel.