(1. 北京科技大学 国家材料腐蚀与防护科学数据中心，北京 100083；
2. 北京科技大学 新材料技术研究院，北京 100083)
摘 要: 随着材料服役环境的恶化，Zn-Al-Mg (ZAM) 镀层因其具有优良的耐蚀性而受到广泛关注。本文从合金元素入手，探讨了其对ZAM中合金相的形成乃至镀层耐蚀性能的影响及作用机制；同时通过对ZAM在大气环境中的腐蚀行为特征的归纳，从腐蚀产物的角度阐述了镀层的腐蚀机理。一般认为，MgZn2作为阳极优先被腐蚀，从而产生Mg2+和Zn2+。Mg2+可以抑制腐蚀环境pH值的升高，从而防止在高pH值条件下保护性腐蚀产物Zn5(OH)8Cl2·H2O向非保护性腐蚀产物ZnO转变。Zn2+的产生更有利于形成保护性腐蚀产物LDH(双层氢氧化物)。但目前的研究仍存在不足，特别是对高铝含量的ZAM镀层中复杂的相结构所带来的腐蚀机理仍不明晰。这些都是未来ZAM镀层的研究重点。
关键字: 锌铝镁合金镀层；合金相；耐蚀性；大气腐蚀；腐蚀产物
（1. National Material Corrosion and Protection Data Center, University of Science and Technology Beijing, Beijing 100083, China;
2. Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:With the deterioration of the service environment of materials, Zn-Al-Mg (ZAM) coatings have been received widespread attention due to their excellent corrosion resistance. From the perspective of alloying elements, this article discussed its influence on the formation of alloy phases in ZAM and even the corrosion resistance of the coating and its mechanism of action. At the same time, through the summary of the corrosion behavior of ZAM in the atmosphere, the corrosion mechanism of the coating was explained from the perspective of corrosion products. It was generally believed that MgZn2 was preferentially corroded as an anode, thereby generating Mg2+ and Zn2+. Mg2+ can inhibit the pH increase of the corrosive environment, thereby preventing the protective corrosion product (Zn5(OH)8Cl2·H2O) from transforming to the non-protective corrosion product (ZnO) at high pH scale. The production of Zn2+ is more conducive to the formation of protective corrosion products (LDH; double-layer hydroxide). However, the current research still has certain shortcomings. Especially, the corrosion mechanism caused by the complex phase structure in the ZAM coating with high aluminum content is still unclear. These are the focus of future research on ZAM coatings.
Key words: Al-Zn-Mg alloy coating; alloy phase; corrosion resistance; atmospheric corrosion; corrosion products
