Research on hot-dipped Zn-6%Al-3%Mg alloy coatings intermetallics layer growth

• Published in: Cai liao gong cheng = Journal of materials engineering no. 7; pp. 54 - 60
• Main Authors: Tong, Chen, Su, Xu-Ping, Li, Zhi, Wang, Jian-Hua, Wu, Chang-Jun, Peng, Hao-Ping, Xu, Peng
• Format: Journal Article
• Language: Chinese
• Published: 01.07.2013
• Subjects: Coatings; Diffusion; Diffusion layers; Interface reactions; Intermetallics; Iron; Zinc; Zinc base alloys
• ISSN: 1001-4381
• DOI: 10.3969/j.issn.1001-4381.2013.07.011

Zn-6% Al alloy and Zn-6%Al-3%Mg alloy coating was galvanized by hot-dip method in different immersion time to get intermetallics layer with different thickness. Samples were characterized by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) to investigate the interfacial reaction and phase composition of intermetallics layer. It is found that the hot-dip Zn-6%Al-3%Mg alloy coating intermetallics layer consisted of the Fe-Al-Zn intermetallics compound, the Fe-Al-Zn intermetallics layer inhibited formation of the brittleness Fe-Zn compound layer. The addition of Mg into the Zn-6%Al bath promotes the interface reaction and growth of the intermetallics layer and makes it dense. With the Mg addition, the trend of the diffusion path moving gradually to the line connecting with two diffusion component points was inhibited, and intermetallics layer would be dense. Meanwhile, the intermetallics layer becomes too stable to be eroded by the liquid zinc. The thickness of the coating increases with prolonging of dipping time. The growth of the coating in Zn-6%Al-3%Mg bath is controlled by diffusion.