5A06和2A12铝合金在硫酸-己二酸中阳极氧化行为及膜层电化学性能

Oxidation behavior of 5A06 and 2A12 aluminum alloys in sulfuric- adipic acid and electrochemical property of anodic oxide film

以5A06和2A12铝合金为研究对象,研究了Al-Mg和Al-Cu合金在硫酸-己二酸中阳极氧化行为及其氧化膜的电化学性能,分析合金相对铝合金阳极氧化膜层结构以及耐蚀性的影响.采用场发射扫描电子显微镜(FE-SEM)进行表面形貌观察,采用动电位极化曲线、电化学阻抗谱(EIS)进行膜层的电化学性能评价.结果表明:2A12铝合金恒电压阳极氧化过程中出现两个电流峰值,这说明含铜相的溶解会影响阳极氧化过程;2A12铝合金膜层孔洞不规整,连通现象严重,含铜相的富集促进了氧气的产生,影响了氧化膜的微观结构;相同浸泡时间下,5A06铝合金氧化膜自腐蚀电位更高,自腐蚀电流更低,具有较高的耐蚀性,这是由于Al-Cu合金的孔隙率要比Al-Mg合金高.

Anodic films of 5A06 and 2A12 aluminum alloys were obtained in sulfuric-adipic acid. The influence of alloy phase on anodie oxidation behavior, and the structure and corrosion resistance of the oxide film were analyzed. Electrochemical results were completed by the polarization curve and electrochemical imped- ance spectroscopy （EIS） , and mierostrueture characterization of the anodie film was carried out by field emission-scanning eleetronmieroseopy （FE-SEM）. 2A12 aluminum alloy showed two current peaks during anodiza- tion process, which shown that the dissolution of copper phase would influence the process of anodie oxidation. The pores of 2A12 anodie oxide film are not neat and have serious connectivity. Enrichment of copper phase promotes the production of oxygen. With the same soaked time, the corrosion potential of anodie oxide film on 5A06 is higher and corrosion current is lower than those of 2A12. The corrosion resistance of anodie oxide film on 5A06 is better. There properties all attributed to the higher porosity of Al-Cu alloy than that of Al-Mg alloy.