镁合金表面自愈合涂层进展

    所谓自愈合涂层是指涂层遭受一定的破坏时，在外界未输入（或少量）影响，能够对受损区进行一定的自我修复，从而达到继续保护基体或恢复特定功能的涂层。

    狭义上而言，涂层自愈合是对涂层本身的修复，即利用修复剂的反应；从广义
上讲，涂层自愈合也可以是对涂层功能（尤指防腐蚀）的恢复，主要利用缓蚀剂。

    自愈合涂层能够一定程度地修复表面涂层的损伤，延长涂层的使用寿命，因此，广泛应用于镁合金表面处理领域。结合经典的自愈合涂层模型和理论，综述了镁合金表面自修复涂层的最新相关研究成果。
    铬酸盐转化膜是一种最典型的化学转化膜，其利用修复剂之间的化学反应来达到修补涂层损伤的目的，工艺简单，容易实现，但其修复涂层效果极大地受到修复剂填埋量的影响。以微囊微管为代表的微容器型自愈合涂层进一步丰富了自愈合涂层的设计理念，但因其工艺相对复杂、缓蚀剂装载量有限等问题也颇受限制，而利用多孔材料装载修复剂的等类微容器涂层是近期比较新颖的涂层设计思路。最新的研究工作则主要围绕多功能化的自修复复合涂层展开，自愈合效果往往只是复合涂层的一部分功能，也不再是对于涂层本身的修复，而更加注重利用涂层本身与腐蚀产物的共同作用达到对涂层功能的修复；无机类与聚合物类修复剂复合使用，共同增强自愈合效果。另外，根据实际应用条件设计的触发式自愈合，更贴近现实。

      此文刊载于《表面技术》2019第三期由重庆大学教授潘复生院士负责的专题—镁合金腐蚀与防护。2019,48(3):1-9. DOI：10.16490/j.cnki.issn.1001-3660.2019.03.001

图1 复合涂层结构及自修复机理示意图
Fig. 1 Schematic diagram of SSLbL coating structure and self-healing mechanism

           Ref [1]: ZHAO Y B,  et al. Materials letters, 2019, 237: 14-18.

Recent Development of Self-healing Coating on Magnesium Alloys: A Review

Self-healing coating has been widely applied into surface treatment of magnesium alloys, due to the fact that it can repair the mechanical damage and prolong the in-service life. Based on classical self-healing coating models and theories, the cutting-edge researches of self-healing coatings on magnesium alloys are reviewed. Chromate chemical conversion coating, one of chemical conversion coatings, is used to renew itself by inhibitors. This method is simple and easy to implement, but it is highly affected by the amount of corrosion inhibitors. The micro-container self-healing coatings, such as microcapsule and microtubules, enrich design concept of self-healing coatings, but it is also limited due to the relatively complicated process and the loadings of inhibitor. Recently, porous materials are used as micro-container, which is a novel coating design concept. Multifunctional composite coatings are the focus in recent research, and self-healing effect is usually only one of its functions. New self-healing coatings not only focus on multi-functional composite coatings, but also pay more attention to repair functions. Inorganic and polymer-based healing agents are usually combined to enhance self-healing effect. Also, self-healing coatings designed and triggered by actual condition are closer to the reality.

Origin: Zi-You Ding, Lan-Yue Cui, Rong-Chang Zeng. Surface Technology, 2019,48(3):1-9. DOI：10.16490/j.cnki.issn.1001-3660.2019.03.001