摘要
近年来,由于Zn-Al-Mg镀层具有优异的耐腐蚀性能,其在多种服役环境中逐渐规模化应用,但是其在不同的环境中的腐蚀行为及机理研究尚不充分。采用硅藻土模拟土壤实验室加速腐蚀法研究热浸镀Zn-11Al-3Mg镀层在模拟华南地区、西北地区、北美地区和欧洲地区土壤中的腐蚀行为及机理。结果表明:Zn-Al-Mg镀层在4个区域的土壤中均产生保护性腐蚀产物,埋片12个月镀层仍可对钢基体起到防护作用。Zn-Al-Mg镀层在不同土壤中的腐蚀速率值排序为华南>西北>欧洲≈北美。土壤环境的pH值、含盐量和Cl^(-)含量影响镀层的腐蚀行为:华南地区土壤的pH值较低,H^(+)促进了阴极去极化过程,从而加速腐蚀过程。西北地区土壤含盐量高且Cl^(-)浓度较高,高含盐量使镀层处于强电解质环境中,加速镀层腐蚀;Cl^(-)因其半径小且具有侵蚀作用,破坏致密的保护性腐蚀产物,使镀层发生点蚀。北美地区和欧洲地区近中性土壤环境使镀层腐蚀程度相对轻微。镀层腐蚀后生成了致密稳定的腐蚀产物对镀层起到良好的保护作用,在不同土壤环境中腐蚀产物主要由Zn_(5)(OH)_(8)Cl_(2)·H_(2)O、Zn_(5)(CO_(3))_(2)(OH)_(6)和Zn_(4)SO_(4)(OH)_(6)·H_(2)O组成,Zn-Al-Mg镀层在模拟土壤环境中的腐蚀与土壤环境中的离子参与腐蚀过程密切相关。
In recent years,due to the excellent corrosion resistance of Zn-Al-Mg coatings,they have gradually been applied on a large scale in various service environments.However,the research on their corrosion behavior and mechanism in different environments is still insufficient In this work,diatomaceous earth was employed to simulate soil in a laboratory accelerated corrosion test,to investigate the corrosion behavior and mechanisms of hot-dip Zn-11Al-3Mg coatings under conditions simulating the soils of South China,Northwest China,North America and Europe.Results showed that protective corrosion products formed on the Zn-Al-Mg coating across all four soil regions,and the coating continued to provide effective protection to the steel substrate after 12 months of burial.The corrosion rate of the Zn-Al-Mg coating across the tested different soil environments followed the order:South China>Northwest China>Europe~North America.Moreover,the corrosion behavior of the coating was influenced by the soil's pH,salinity and Cl^(-) content:the relatively low pH of the soil in South China led to a high concentration of H^(+),which promoted the cathodic depolarization process,thereby accelerating the overall corrosion.The soil in Northwest China had a high salt content and a relatively high concentration of Cl^(-).The high salt content placed the coating in a strong electrolyte environment,accelerating the corrosion of the coating.Due to its small ionic radius and erosive effect,Cl^(-) destroyed the dense protective corrosion products,causing pitting corrosion on the coating.By comparison,the near-neutral soil environments in North America and Europe caused relatively mild corrosion of the coating.After corrosion,the coating formed dense and stable corrosion products that provided excellent protection to the coating itself.Furthermore,the corrosion products in different soil environments primarily consisted of Zn_(5)(OH)_(8)Cl_(2)·H_(2)O、Zn_(5)(CO_(3))_(2)(OH)_(6) and Zn_(4)SO_(4)(OH)_(6)·H_(2)O.The corrosion of the Zn-Al-Mg coating in simulated soil conditions was closely related to the involvement of ions from the soil environment in the corrosion process.
作者
杨德松
姚莹
王瑾
谯德高
张文娟
YANG Desong;YAO Ying;WANG Jin;QIAO Degao;ZHAN Wenjuan(School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China;State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;Jiuquan Iron and Steel(Group)Co.,Ltd.,Jiayuguan 735100,China)
出处
《材料保护》
2025年第9期91-102,共12页
Materials Protection
基金
肃省重大科技项目(22ZD6GA008)
国家自然科学基金(51703088,52262013)
2018年重点实验室高分子材料开放基金项目(KF-18-03)
兰州理工大学红柳青年基金(061805)
甘肃省自然科学基金资助项目(21JR7RA259)
甘肃省青年博士项目(2021QB-048)。
关键词
热浸镀
Zn-Al-Mg镀层
耐蚀性
土壤腐蚀
腐蚀行为
hot-dip plating
Zn-Al-Mg coating
corrosion resistance
soil corrosion
corrosion behavior
