陈翠,王瑾,陈娜娜,刘倩倩,张新,肖葵.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,LIU Qian-qian,ZHANG Xin,XIAO Kui.Accelerated Indoor Corrosion Behavior and Mechanism of Galvanized Steel in Simulated Acid Rain Atmospheric Environment[J].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 |
| Accelerated Indoor Corrosion Behavior and Mechanism of Galvanized Steel in Simulated Acid Rain Atmospheric Environment |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.06.029 |
| 中文关键词: 热浸镀锌钢 酸雨大气 室内加速试验 腐蚀机制 |
| 英文关键词:hot-dip galvanized steel acid rain atmosphere indoor accelerated experiment corrosion mechanism |
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| Author | Institution |
| CHEN Cui | Center Iron and Steel Research Institute, Gansu Jiu Steel Group Hongxing Iron & Steel Co., Ltd., Gansu Jiayuguan 735100, China |
| WANG Jin | Center Iron and Steel Research Institute, Gansu Jiu Steel Group Hongxing Iron & Steel Co., Ltd., Gansu Jiayuguan 735100, China |
| CHEN Na-na | Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China |
| LIU Qian-qian | Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China |
| ZHANG Xin | Testing Center of USTB Co., Ltd., Beijing 100083, China |
| XIAO Kui | Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China |
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| 中文摘要: |
| 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 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 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ZnSO4.xH2O和Na2ZnSO4.4H2O，并且由截面形貌可知，镀层在酸雨环境中易被破坏。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。 |
| 英文摘要: |
| 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 (1±0.1) 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 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 ZnSO4.xH2O and Na2ZnSO4.4H2O. The insoluble corrosion product Zn4SO4(OH)6 had a certain protective effect on the coating. However, as the corrosion intensified, it would decompose into Na2ZnSO4.4H2O. 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 loss of protection of the coating and increase the electrochemical reaction rate at the interface, causing further corrosion of the steel. Therefore, the protective effect of the coating completely fails after 120 days of accelerated corrosion test. |
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