目的 对铝合金铬酸阳极氧化后显现出的表面缺陷及原因进行分析。 方法 通过扫描电镜观察试样表面缺陷处的形貌,通过金相显微镜观察缺陷处的金相组织,通过能谱仪对缺陷处的腐蚀产物进行分析。 结果 铝合金通过铬酸阳极氧化后,基体的缺陷处会在铬酸溶液中产生沿晶界腐蚀。 结论 材料本身含有一定量的 Cu,Ni,Mg,Fe 等元素,在热处理过程中,这些元素在晶界处富集形成偏析相,从而造成金属基体在铬酸溶液中的腐蚀。

Objective To analyze the surface defects of the aluminum alloy substrate after chromic acid anodizing and its cause.Methods The morphology, microstructure and corrosion products of the defects were analyzed by scanning electron microscopy ( SEM) , metallurgical microscopy and energy dispersive spectrometer ( EDS) , respectively. Results The defects on the substrate of the aluminum alloy could be caused by the intergranular corrosion when treated by chromic anodizing. Conclusion The elements of Cu, Ni, Mg and Fe could be enriched to form segregation in the process of heat treatment to cause the corrosion of substrate in the chromic acid solution.