2024-T3铝合金中第二相对阳极氧化膜层组织结构和耐蚀性的影响

Effect of second phase in 2024-T3 aluminum alloy on microstructure and corrosion resistance of its anodic oxidation film

[目的]2024-T3铝合金中的第二相会影响其表面阳极氧化膜层的生长,进而影响膜层的组织结构和耐蚀性。[方法]采用环保型苹果酸-硫酸体系对2024-T3铝合金进行阳极氧化处理。通过中性盐雾试验,结合腐蚀前后样品不同区域的微观形貌观察和元素组成分析,研究了基体的第二相对阳极氧化膜层结构和耐蚀性的影响,并探讨了膜层的腐蚀失效机理。[结果]基体第二相对应部位的阳极氧化膜层致密性较差,存在微孔和起皮现象,这些是点腐蚀的主要根源。[结论]本文的研究结果可为航空领域铝合金阳极氧化工艺的改进提供理论依据和实验数据支持。

[Introduction]The existence of second phases in 2024-T3 aluminum alloy affects the growth of anodic oxidation film,which in turn affects the microstructure and corrosion resistance of the anodic oxidation film.[Method]2024-T3 aluminum alloy was anodized in an environmentally friendly bath mainly consisting of malic acid and sulfuric acid.The effect of second phase in substrate on the microstructure and corrosion resistance of anodic oxidation film was studied through neutral salt spray test,in combination with micromorphology observation and elemental composition analysis at different areas of anodic oxidation film before and after being corroded.The corrosion failure mechanism of anodic oxidation film was also discussed.[Result]The anodic oxidation film formed at the position with second phase had poor compactness with micropores and peeling phenomenon,which are the main causes of pitting corrosion.[Conclusion]The findings of this paper can provide a theoretical basis and experimental data support for the improvement of aluminum alloy anodization in aerospace field.