不同厚度锌铝镁合金镀层的耐腐蚀性能  

Corrosion resistance of Zn-Al-Mg alloy coatings with different thicknesses

作　　者：张晨 刘顺明[1] 王长成 王智锋[1] 庞二帅 黎敏 ZHANG Chen;LIU Shunming;WANG Changcheng;WANG Zhifeng;PANG Ershuai;LI Min(Shougang Jingtang Iron&Steel United Co.,Ltd.,Tangshan 063200,China;Research Institute of Technology of Shougang Group Co.,Ltd.,Beijing 100041,China)

机构地区：[1]首钢京唐钢铁联合有限责任公司,河北唐山063200 [2]首钢集团有限公司技术研究院,北京100041

出　　处：《电镀与涂饰》2024年第7期92-100,共9页Electroplating & Finishing

摘　　要：[目的]锌铝镁(Zn-Al-Mg)合金镀层作为一种新型高耐蚀性镀层,其厚度对耐蚀性具有显著影响。[方法]通过辉光放电光谱仪(GDS)、扫描电镜(SEM)、电化学工作站等仪器测试,对比了Zn-Al-Mg合金镀覆量为80、120和180 g/m^(2)的镀锌钢(分别用ZM80、ZM120和ZM180表示)在中性盐雾环境下的耐蚀性。[结果]ZM80、ZM120和ZM180在中性盐雾试验中出现红锈的时间分别为840、1176和1512 h。三者的腐蚀过程包括钝化膜保护、锌层阻隔保护、锌层电偶保护和基体腐蚀4个阶段,其中钝化膜的保护作用与其均匀性有较大关联。ZM120和ZM180的划叉试样在不同时间段的红锈面积与未划叉试样相比无明显区别,这主要归因于Zn-Al-Mg合金镀层在破损区域形成的致密腐蚀产物有效减缓了腐蚀进程。[结论]不同厚度Zn-Al-Mg合金镀层的防腐能力不同,实际生产中可以根据应用场景选择镀层厚度合适的镀锌铝镁合金钢。[Introduction]Zn-Al-Mg alloy coating is a new type of coating with excellent corrosion resistance,which is related to its thickness.[Method]The corrosion resistance to neutral salt spray of the steels coated with 80,120,and 180 g/m^(2) of Zn-Al-Mg alloy(coded as ZM80,ZM120,and ZM180,respectively)was compared by glow discharge spectrometry(GDS),scanning electron microscopy(SEM),and electrochemical measurements.[Result]Red rust occurred on ZM80,ZM120,and ZM180 after neutral salt spray test for 504,840,and 1200 h,respectively.The corrosion of the Zn-Al-Mg alloy coated steel underwent four stages including protection of passivation film,barrier of zinc coating,galvanic protection of zinc coating,and corrosion of steel substrate.The protection of passivation film is closely related to its uniformity.The red rust areas of scratched ZM120 and ZM180 specimens were not significantly different from that of the unscratched ones at different stages of neutral salt spray test,which is mainly due to the fact that the compact corrosion products forming at the damaged position of Zn-Al-Mg alloy coating slow down the corrosion process.[Conclusion]Zn-Al-Mg alloy coatings with different thicknesses feature different anticorrosion property.It is better to determine the coating thickness according to the application scenarios.

关 键 词：锌铝镁合金 镀层厚度 红锈 腐蚀产物 钝化膜 

分 类 号：TQ153.2[化学工程—电化学工业]