镁合金的腐蚀特性及防护技术

镁合金作为最轻的金属结构材料,在汽车、3C、国防军工、航空航天等领域具有广阔的应用前景,但耐蚀性较差是其大规模应用的瓶颈。介绍了镁合金的腐蚀机理,包括全面腐蚀、局部腐蚀、电偶腐蚀等,以及影响镁合金耐腐蚀的因素,根据不同介质中的具体腐蚀情况,对影响镁合金腐蚀的三大因素作了重点介绍,从而总结出提高镁合金防腐性能的两个研究方向,一是改善镁合金的本征耐蚀性,即通过优化合金成分,改善镁合金的微观组织等方式提高材料的耐蚀性;二是采用表面防护处理技术,通过表面防护层对基体进行保护,隔离腐蚀介质与基体。然后详细综述了净化合金成分、开发新型耐蚀镁合金、改善镁合金的表层微观组织等提高镁合金本征耐蚀性的方法,以及有机/聚合物、金属/化合物镁合金耐蚀涂层的研究现状。最后指出了镁合金防腐技术研究过程中存在的问题和今后的发展方向。

Corrosion Characteristic and Protection Techniques for Mg Alloys

ABSTRACT:Magnesium alloy is the lightest metallic structural material, and has broad application prospects in fields of automo-bile, 3C, national defence, aerospace and so on. However, the poor anti-corrosion property has become the bottleneck for its large-scale applications. The corrosion mechanisms of comprehensive corrosion, local corrosion and galvanic corrosion etc. of magnesium alloys as well as the factors affecting the corrosion resistance of magnesium alloy were elucidated in the paper. Based on the corro-sion resistance of magnesium alloy in different media, the three major factors affecting corrosion of magnesium alloys were intro-duced, and the two study directions to improve magnesium alloy′s corrosion resistance were summarized:one was to improve mag-nesium alloy′s intrinsic corrosion resistance, i. e. to improving the corrosion resistance of the material by optimization of alloy com-position and improving magnesium alloy′s microstructure. The other way was to use surface protection treatment technology, i. e. to separate the basis materials and the corrosion medium by using protective coatings to protect the basis materials. Then the methods to enhance the intrinsic corrosion resistance of magnesium alloy were reviewed, including purification of magnesium alloy′s compo-nents, inventing new kinds of anti-corrosion magnesium alloy, improving magnesium alloy′s surface microstructure, etc. The re-search status of organic polymerization and metallic compound corrosion resistant coatings for magnesium alloy were also summa-rized. Furthermore, the existing problems in the corrosion protection technologies of magnesium alloys and the future development orientation were pointed out.