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采用腐蚀质量损失、扫描电子显微镜、X射线衍射仪、线性极化等测试手段,研究无光照、半光照及全光照三种实验条件对Q450NQR1耐候钢在干湿交替条件下腐蚀行为的影响规律.结果表明:光照对实验钢干湿交替腐蚀过程影响显著.实验钢在腐蚀前期(48 h)腐蚀速率大小依次为半光照、无光照和全光照,腐蚀中后期(72~96 h)腐蚀速率由大到小依次为半光照、全光照和无光照.腐蚀宏观形貌有明显差别,无光照时试样腐蚀产物呈淤泥状分布整个表面,有光照条件时腐蚀产物则呈颗粒状分布,但全光照条件时腐蚀产物颗粒更细且孔隙更小.另外,三种条件下腐蚀产物物相组成一致,但含量有所不同.线性极化测试得出96 h极化电阻由大到小依次为无光照、全光照和半光照,这一结果与通过腐蚀失重得出的腐蚀速率结果一致.
The corrosion behavior of Q450NQR1 weathering steels under alternating dry-wet conditions was studied by using corrosion loss, scanning electron microscopy, X-ray diffraction and linear polarization test. The results show that light has a significant influence on the process of alternating wet and dry corrosion of experimental steel.The corrosion rate of experimental steel in the early period of corrosion (48 h) is semi-light, no light and total light, and the corrosion rate in mid-and late-period (72-96 h) The results showed that there was a significant difference in the macroscopic appearance of the samples when the samples were exposed to light, and the corrosion products of the samples were distributed as a whole, In the light conditions, the corrosion product particles are finer and the pores are smaller.In addition, the corrosion products in the three conditions have the same phase composition, but the content is different.The linear polarization test shows that the 96 h polarization resistance is in descending order Light, full light, and semi-light, this result is consistent with the corrosion rate resulting from corrosion weight loss.