模拟酸雨大气环境镀锌钢的室内加速腐蚀行为和机理_陈翠.pdf

第 52 卷 第 6 期 表面技术 2023 年 6 月 SURFACE TECHNOLOGY 327 收稿日期：20220514；修订日期：20220909 Received：2022-05-14；Revised：2022-09-08 作者简介：陈翠（1987），女，工程师，主要研究方向为金属涂镀后表面处理及耐蚀性能。Biography：CHEN Cui(1987-),Female,Engineer,Research focus:surface treatment and corrosion resistance of metal coating.通讯作者：肖葵（1969），男，博士，研究员，主要研究方向为材料腐蚀与防护。Corresponding author：XIAO Kui(1969-),Male,Doctor,Researcher,Research focus:corrosion and protection of materials.引文格式：陈翠，王瑾，陈娜娜,等.模拟酸雨大气环境镀锌钢的室内加速腐蚀行为和机理J.表面技术,2023,52(6):327-336.CHEN Cui,WANG Jin,CHEN Na-na,et al.Accelerated Indoor Corrosion Behavior and Mechanism of Galvanized Steel in Simulated Acid Rain Atmospheric EnvironmentJ.Surface Technology,2023,52(6):327-336.模拟酸雨大气环境镀锌钢的 室内加速腐蚀行为和机理 陈翠1，王瑾1，陈娜娜2，刘倩倩2，张新3，肖葵2（1.甘肃酒钢集团宏兴钢铁股份有限公司 钢铁研究院，甘肃 嘉峪关 735100；2.北京科技大学 新材料技术研究院，北京 100083；3.北京科大分析检验中心有限公司，北京 100083）摘要：目的目的 采用室内加速试验方法研究热浸镀锌钢在模拟酸雨大气环境中的腐蚀行为和机理。方法方法 主要采用失重法对试样的腐蚀动力学进行研究，采用 EDS、XRD 和 XPS 对试样进行腐蚀产物成分分析，通过SEM 和共聚焦显微镜观测试样表面形貌，采用 EIS 对试样表面涂层的保护性能进行检测。结果结果 在模拟酸雨大气环境中，厚度损失与时间呈幂函数关系，腐蚀大致是一个减速过程但在 104 d 后加速，在 120 d 后试样表面出现红锈和密集、深而窄的点蚀坑。主要腐蚀产物有 ZnO、Zn4SO4(OH)6及可溶性产物 ZnSO4xH2O 和Na2ZnSO44H2O，并且由截面形貌可知，镀层在酸雨环境中易被破坏。结论结论 在模拟酸雨大气环境中，热浸镀锌本身的耐蚀性很快失效，腐蚀速度加快直至生成的腐蚀产物在缺陷处形成较为完整的产物膜，对镀层的腐蚀具有一定抑制作用。但是酸雨环境中腐蚀产物膜较薄，易被破坏，这种溶解会使镀层失去保护，进一步腐蚀。关键词：热浸镀锌钢；酸雨大气；室内加速试验；腐蚀机制 中图分类号：TG174 文献标识码：A 文章编号：1001-3660(2023)06-0327-10 DOI：10.16490/ki.issn.1001-3660.2023.06.029 Accelerated Indoor Corrosion Behavior and Mechanism of Galvanized Steel in Simulated Acid Rain Atmospheric Environment CHEN Cui1,WANG Jin1,CHEN Na-na2,LIU Qian-qian2,ZHANG Xin3,XIAO Kui2(1.Center Iron and Steel Research Institute,Gansu Jiu Steel Group Hongxing Iron&Steel Co.,Ltd.,Gansu Jiayuguan 735100,China;2.Institute for Advanced Materials and Technology,University of Science and Technology Beijing,Beijing 100083,China;3.Testing Center of USTB Co.,Ltd.,Beijing 100083,China)ABSTRACT:To investigate the corrosion behavior and mechanism of hot-dip galvanized steel in the simulated acid rain atmosphere,the indoor cyclic accelerated test was adopted.Each cycle process was composed of acid salt spray conditions,dry conditions,and wet conditions for 8 h.The salt solution used in the acid salt spray condition was(10.1)g/L NaHSO3,and the pH value was about 2.5.When the test reached the four cycles of 24,56,104,and 120 d,the samples were taken out for further 328 表 面 技 术 2023 年 6 月 analysis.The corrosion kinetics of the samples was mainly studied by the weight loss method.Scanning electron microscope(SEM)was used to analyze the surface and cross-sectional micro-morphology of the corrosion samples,combined with an energy dispersive spectroscopy(EDS)to analyze the elemental composition and distribution.The components of corrosion products were characterized by X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).Then,the formation process of the corrosion products was obtained according to the product composition in different cycles.The surface morphology of samples after rust removal in different test cycles was observed by a 3D laser confocal microscope,and the pitting depth was measured.The protective properties of the coating on the sample surface were characterized by electrochemical impedance spectroscopy(EIS)measurements.Combined with these characterization methods,the corrosion mechanism of the galvanized steel in the simulated acid rain atmospheric environment was clarified.In this environment,the thickness loss was a power function of time.At the same time,with the extension of the test time,the corrosion rate of the hot-dip galvanized plate decreased continuously,and then showed an upward trend in the last cycle.However,during the whole corrosion process,the instantaneous corrosion rate of the zinc coating gradually decreased.After 120 days,the thickness reduction of the zinc coating was close to the original thickness of the coating,with serious red rust and intensive pitting corrosion observed on the sample surface,and the pitting was deep and narrow.In addition,it can be seen from the cross-sectional morphology that a double-layer corrosion product layer was formed.The main corrosion products were ZnO,Zn4SO4(OH)6 and the soluble products were ZnSO4xH2O and Na2ZnSO44H2O.The insoluble corrosion product Zn4SO4(OH)6 had a certain protective effect on the coating.However,as the corrosion intensified,it would decompose into Na2ZnSO44H2O.In the simulated acid rain atmospheric environment,the corrosion resistance of the hot-dip galvanized layer itself quickly fails,and the corrosion rate is accelerated till the generated corrosion products form a relatively complete product film at the defects,which has a certain inhibitory effect on the corrosion of the coating.However,on the one hand,it can be known from the cross-sectional morphology that the corrosion product film in the acid rain environment is thin and easy to be damaged.And on the other hand,acid aerosols will promote the dissolution of the relatively stable corrosion products,resulting in the