镁合金表面改性与防护研究进展

Recent Progress on the Surface Modification and Protection of Magnesium Alloys

镁合金是最轻的金属结构材料,具有比强度高、比刚度高、导电导热性好、生物相容性好等优点,在汽车、航空航天、电子、生物医学等领域有着广阔的应用前景。然而,镁自身化学活性极高且其表面的原生氧化膜疏松多孔,无法有效保护基底,往往在各加工工序间就会发生表面腐蚀。严重的腐蚀问题已经成为制约镁及其合金应用与发展的主要短板,因此,对镁合金进行表面防护处理是极为重要的。现阶段,镁合金的表面处理方法虽然种类繁多,但防护效果良莠不齐。重点综述了两种常用的镁合金表面改性技术--化学转化膜技术和微弧氧化技术的新进展,并介绍了一种基于活性CO2处理提高镁合金耐蚀性的新技术,以及仿生超疏水表面在提升镁合金耐蚀性上的应用,最后,对镁合金表面改性与防护的未来发展方向进行了展望。

Magnesium( Mg) alloys are the lightest structural metal material with high strength-to-weight ratio,good thermal( electrical) conductivity and biocompatibility,having broad application prospects in automotive,aerospace,electronics and biomedical industries. As advanced light metals,Mg alloys are promising to replace the traditional materials,however,Mg is too reactive,and its native oxide scale is porous and cannot protect the base metal from environmental corrosion effectively. The low corrosion resistance has severely reduced the competitiveness of Mg alloys,and limits their applications. To this end,the surface protection of Mg alloys is indispensable. At present,there have been many kinds of surface treatment methods,but their protection effects are different. Here,we focus on the recent progress of two frequently used technologies,the chemical conversion and micro-arc oxidation. A new method based on the excited CO2 for surface modification of Mg alloys and the biomimetic superhydrophobic surfaces for corrosion protection of Mg alloys are introduced as well. In the end,we discuss the future direction of the surface protection of Mg alloys.