6xxx系铝合金表面腐蚀及其防腐的研究现状

6xxx系(Al-Mg-Si)铝合金作为综合性能良好的中强铝合金,因其较小的密度、良好的耐蚀性和成形性等优点,被广泛应用在航空航天、交通运输和建筑机械等领域。然而,该类铝合金在工业应用中依然存在腐蚀问题,造成巨大的经济损失,带来严重的安全隐患。针对这一问题,首先介绍了6xxx系铝合金的腐蚀类型,总结了影响其耐蚀性的影响因素,重点介绍了合金元素对其耐蚀性的影响。已有的研究结果表明:铝合金中的Mg、Si、Cu、Zn等元素显著影响合金的耐蚀性能,过量Si和Cu元素的添加增加了铝合金的晶间腐蚀敏感性;适当地添加过渡族金属元素及稀土元素,可有效改善铝合金的耐蚀性。随后,分析了提高铝合金耐蚀性能的途径,包括改善热处理工艺、优化合金成分及添加复合物等方法,并介绍了几种典型的表面防腐处理工艺,如阳极氧化技术、微弧氧化技术、化学转化膜技术、电镀及化学镀技术。最后总结了以上防护途径存在的一些问题,并指出了耐蚀铝合金的主要发展方向。

Surface Corrosion and Corrosion Prevention of 6xxx-series Aluminium Al-loy

As aluminum alloys of medium strength and good comprehensive performance, 6xxx-series (Al-Mg-Si) aluminum alloys have been widely used in aerospace, transportation, construction machinery and other fields due to small density, good corrosion resistance and formability. However, these alloys still face corrosion problem in industrial applications, the corrosion will cause huge economic losses and bring serious security risks. In respect of this problem, corrosion types of 6xxx-series aluminum alloys were introduced firstly, factors affecting corrosion resistance of 6xxx-series aluminum alloys were summarized, and influences of alloying elements on corrosion resistance were emphatically introduced. Results of existing studies showed that Mg, Si, Cu, Zn and other elements in the aluminum alloys significantly affected the corrosion resistance, excessive Si and Cu elements could improve intergranular corrosion susceptibility of the aluminum alloys. The corrosion resistance of aluminum alloys could be improved by adding proper amount of transitional metal elements and rare earth elements. Then, ways of improving corrosion resistance of the aluminum alloys were analyzed, including improving heat treatment process, optimizing alloy composition and adding compounds. Several typical surface preservative treatment processes were introduced, such as anodizing technology, micro-arc oxidation technology, chemical conversion film technology, electroplating and electroless plating technology. Finally, some problems of the above methods were summarized, and main development directions of corrosion-resistant aluminum alloys were pointed out.