钢件双镀ZAM合金镀层的组织及耐蚀性  

Microstructure and Corrosion Resistance of Two-step Hot-dipped ZAM Alloy Coating on Structural Steel

作　　者：吴长军 姚利丽[1,3] 周志嵩 薛烽 朱晨露[1,3] WU Changjun;YAO Lili;ZHOU Zhisong;XUE Feng;ZHU Chenlu(Jiangsu Xingda Steel Tyre Cord Co.,Ltd.,Taizhou 225721,China;School of Materials Science and Engineering,Changzhou University,Changzhou 213164,China;Jiangsu Key Laboratory for Structural and Functional Metal Composite Materials,Taizhou 225721,China;School of Materials Science and Engineering,Southeast University,Nanjing 211189,China)

机构地区：[1]江苏兴达钢帘线股份有限公司,泰州225721 [2]常州大学材料科学与工程学院,常州213164 [3]江苏省结构与功能金属复合材料重点实验室,泰州225721 [4]东南大学材料科学与工程学院,南京211189

出　　处：《材料导报》2021年第S01期434-437,共4页Materials Reports

基　　金：江苏省博士后科研资助计划项目(2018K019B)。

摘　　要：为在钢件上获得高耐蚀性的Zn-6Al-3Mg(ZAM)合金镀层,利用双镀方法,将Q235钢经过常规批量镀锌方法预处理后,先在450℃纯锌浴中预镀3~30 s,然后于并排放置的450℃的Zn-6Al-3Mg合金浴中浸镀5~120 s,利用扫描电镜-能谱仪和电化学分析研究了预镀时间和浸镀时间对双镀ZAM合金镀层组织及耐蚀性的影响。结果表明,双镀ZAM合金可获得表面质量优良的合金镀层,其组织由Fe_(2)Al_(5)-Zn_(x)层、FeAl_(3)-Zn_(x)+Z(液相凝固组织)层及合金凝固层组成。在ZAM合金浴中浸镀10 s后,预镀锌形成的Fe-Zn化合物层就已被完全侵蚀,转变成FeAl_(3)-Zn_(x)+Z层,它能在镀层中稳定存在,其厚度随预镀锌时间的延长而增加。同时,在钢基体与镀层界面上会形成很薄的Fe_(2)Al_(5)-Zn_(x)层。Fe_(2)Al_(5)-Zn_(x)和FeAl_(3)-Zn_(x)+Z层的厚度均不随浸镀时间的延长而增加。此外,电化学分析证实,双镀ZAM合金镀层耐蚀性明显优于纯锌镀层。通过双镀法获得的这种具有FeAl_(3)-Zn_(x)+Z层的高耐蚀的ZAM合金镀层将为钢件新镀层开发奠定基础。To obtain Zn-6Al-3Mg(ZAM)alloy coating,which has high corrosion resistance,the Zn-6Al-3Mg alloy coatings were prepared on Q235 steel by two-step hot-dip method.The Q235 steel,which was pretreated by conventional galvanizing method,was pre-dipped in pure zinc bath at 450℃for 3—30's and then immersed in ZAM alloy bath for 5—120 s.The influences of pre-dipping time and immersion time on the microstructure and corrosion resistance of the coating were investigated.Experimental results showed that the ZAM alloy coating with excellent surface quality can be obtained by two-step hot-dip method.The coating was composed of Fe_(2)Al_(5)-Zn_(x),FeAl_(3)-Zn_(x)+Z(solidification structure of the liquid phase)layer and the solidified ZAM alloy layer,while no Fe-Zn compound existed.After immersing in the ZAM bath for 10 s,the Fe-Zn compounds formed during pre-dipping had been totally corroded and turned to FeAl_(3)-Zn_(x)+Z two phases.This layer could stably exist in the coating and its thickness increased with the pre-dipping time.At the same time,very thin Fe_(2)Al_(5)-Zn_(x) layer existed at the interface between steel substrate and coating.It was found that the thickness of both Fe_(2)Al_(5)-Zn_(x) and FeAl_(3)-Zn_(x)+Z two phase layer changed a little with the immersing time in ZAM bath.In addition,it was confirmed that the corrosion resistance of the two-step hot-dipped ZAM coating was better than that of pure zinc coating.This kind of Zn-6Al-3Mg(ZAM)alloy coating with FeAl_(3)-Zn_(x)+Z two-phase layer and high corrosion resistant will help to develop new kind of coa-ting on steel parts.

关 键 词：热浸镀 Zn-6Al-3Mg 双镀 镀层 微观组织 

分 类 号：TG174.[金属学及工艺—金属表面处理]