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以NaCl+NaHSO_3为腐蚀介质,通过周期浸润加速腐蚀实验、腐蚀失重、XRD、XPS、SEM/EDS和极化曲线等,研究了湿热工业-海洋大气环境中,Si对桥梁钢腐蚀行为的影响。结果表明:实验钢的腐蚀过程遵循幂函数分布规律。Si含量由0.25%(质量分数)增加到0.48%,实验钢的耐蚀性提高,但随锈层保护性增强,Si的作用有所减弱。Si在强化铁素体组织、细化腐蚀产物颗粒和促进铁氧化物结晶方面的作用显著,能使锈层的保护性在短时间内得到提升。同时Si在裂纹和锈巢边缘出现富集,一定程度上能帮助修复锈层缺陷。Fe_2SiO_4是Si在锈层中的主要存在形式,具有反尖晶石结构,能增强锈层的稳定性。
The effect of Si on the corrosion behavior of bridge steel was studied by using NaCl + NaHSO_3 as corrosion medium, cyclic corrosion accelerated corrosion test, corrosion loss, XRD, XPS, SEM / EDS and polarization curves. The results show that the corrosion process of experimental steel follows the law of power function distribution. The content of Si increased from 0.25% (mass fraction) to 0.48%. The corrosion resistance of the experimental steel increased, but with the protection of the rust layer enhanced, the effect of Si was weakened. Si plays a significant role in strengthening the ferrite structure, refining the corrosion product particles and promoting the crystallization of iron oxide, so that the protective property of the rust layer is improved in a short period of time. At the same time, Si appears in the edge of the crack and rust nest enrichment, to some extent, can help repair rust defects. Fe2SiO4 is the main form of Si in the rust layer, with anti-spinel structure, can enhance the stability of the rust layer.