Zn-Al-Mg镀层在3.5％NaCl溶液中的腐蚀产物分析
Analysis of corrosion products of zinc-aluminum-magnesium coating in 3.5％NaCl solution
史学星 1张莉霞 1严春莲 1鞠新华1
作者信息
- 1. 首钢集团有限公司技术研究院,北京 100043
- 折叠
摘要
利用扫描电镜(SEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)等多种分析技术对在3.5％NaCl溶液中浸润不同时间(0、3、7和21 d)的Zn-Al-Mg镀层表面的腐蚀产物进行了深入探讨.结果表明:正常Zn-Al-Mg镀层表面主要含Zn、Mg、Al和少量的C、O元素,由白色块状富Zn相、灰色共晶组织MgZn2相和富Al相组成,表面存在极薄的氧化物薄膜.而经过3.5％NaCl溶液腐蚀的Zn-Al-Mg镀层表面Zn、Mg、Al含量明显减少,Fe和O含量明显增多.腐蚀时间由3 d→7 d→21 d,其腐蚀层表面呈现出灰色→白色→橘黄色(腐蚀严重的呈深红色)变化;腐蚀初期产物主要为Mg(OH)2和Zn5(CO3)2·(OH)6,随着腐蚀时间增加,腐蚀产物主要为AlFeO3、Zn5(CO3)2·(OH)6和少量Zn5(OH)6Cl2·H2O,腐蚀时间继续增加到21 d,腐蚀产物以FeO(OH)为主,此外还有少量的Zn5(OH)6Cl2·H2O.
Abstract
The corrosion products on the surface of zinc-aluminum-magnesium coating,which was soaked in 3.5％NaCl solution for different periods(0 d,3 d,7 d,and 21 d),were investigated in depth be means of various analysis techniques including scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).The results showed that the surface of normal zinc-magnesium-aluminum coating mainly contained Zn,Mg,Al and a small amount of C and O elements,which were composed of white blocky Zn-rich phase and gray eutectic structure(MgZn2 phase and Al-rich phase).There was an extremely thin oxide film on the surface.After corrosion by 3.5％NaCl solution,the contents of Zn,Mg and Al on the surface of zinc-magnesium-aluminum coating decreased obviously,while the contents of Fe and O increased significantly.As the corrosion time ranged from 3dto7dto21d,the surface of corrosion layer showed the color change from gray to white to orange yellow(deep red was observed when the corrosion was severe).The initial corrosion products were mainly Mg(OH)2 and Zn5(CO3)2·(OH)6.With the increase of corrosion time,the corrosion products were mainly AlFeO3,Zn5(CO3)2·(OH)6 and a small amount of Zn5(OH)6Cl2·H2O.When the corrosion time further increased to 21 d,the corrosion products were mainly FeO(OH)and a small amount of Zn5(OH)6Cl2·H2O.
关键词
Zn-Al-Mg镀层/腐蚀产物/NaCl溶液Key words
zinc-aluminum-magnesium coating/corrosion product/NaCl solution引用本文复制引用
出版年
2024
NETL
NSTL
万方数据