镁合金丝状腐蚀研究进展

目的镁合金具有许多独特的性能及光明的应用前景,但耐蚀性差制约了其发展。丝状腐蚀作为一种常见的局部腐蚀形态,其破坏性非常大。结合国内外丝状腐蚀的研究成果,从丝状腐蚀产生的原因及发展过程,重点叙述了镁合金丝状腐蚀的特点、腐蚀机理,以及腐蚀环境和微观结构对镁合金丝状腐蚀发展的影响规律。指出了镁合金丝状腐蚀阴极发生的是析氢反应,且腐蚀丝具有折射生长、相随生长等特点;腐蚀介质会优先吸附在自然形成氧化膜的缺陷处,导致腐蚀萌生;第二相、晶粒尺寸和表面处理等微观结构对腐蚀丝的发展有重要影响。同时总结了微区原位技术在镁合金丝状腐蚀研究中的应用,并指出了微区原位技术和传统的腐蚀研究方法相结合是揭示镁合金丝状腐蚀机制的有效途径。最后,对未来镁合金丝状腐蚀机理的研究进行了分析和展望。

Research Progress of Filiform Corrosion on Magnesium Alloy

Magnesium alloy features in various unique properties and promising application prospect. However, its poor corrosion resistance has restained its development. Filiform corrosion, as one of the common localized corrosion forms, has exhibited significant destructive effect. Combined with research results of filiformcorrosion home and abroad, filiform corrosion characteristics, corrosion mechanisms and effect law of corrosion environment and microstructure on the development of filiform corrosion were highlighted in respect of intrinsic causes and development process of filiform corrosion. It was pointed out that the cathodic side was driven by hydrogen evolution reaction during the development of filament corrosion on magnesium alloy, and corrosion filaments featured in refraction growth, accompanying growth. Corrosive mediums preferentially adsorbed on the defects with naturally formed oxide films and induced filiform corrosion. Microstructure including second phase, grain size and surface treatment had important effects on the development of corrosion filaments. Meanwhile, the application of in-situ local technique to the filiform corrosion study of magnesium alloy was summarized. It was indicated that the in-situ local techniques combined with traditional corrosion research methods was an efficient approach to reveal filiform corrosion mechanism of Mg alloy. Finally, the future research focus of filiform corrosion of Mg alloy was analyzed and expected.