AZ31B镁合金/6061铝合金异质金属连接件整体微弧氧化膜的制备及其结构

Preparation and Structure of Overall Micro-Arc Oxidation Film on AZ31B Magnesium Alloy/6061 Aluminum Alloy Dissimilar Metal Connected Part

对AZ31B镁合金和6061铝合金异质金属铆接件进行了微弧氧化,研究了不同时间微弧氧化膜的微观形貌、物相组成、电化学性能、硬度等,对比分析了微弧氧化过程中镁合金、铝合金表面氧化膜的形成过程。结果表明:经过10min的微弧氧化后,该连接件整体被氧化膜包裹,氧化膜与2种合金基体均紧密连接,且均由致密层和疏松层组成;镁合金表面氧化膜主要由MgO、少量硅酸盐和氟化物组成,而铝合金表面氧化膜主要由Al_2O_3及少量硅酸盐组成;微弧氧化提高了连接件中镁合金、铝合金的腐蚀电位,降低了二者的腐蚀电位差,有效缓解了电偶腐蚀的发生。

AZ31B magnesium alloy and 6061 aluminum alloy dissimilar metal riveted part was micro-arc oxidized.The microscopic morphology,phase composition,electrochemical property and hardness of the oxidation film after micro-arc oxidation for different times were studied.The formation process of the oxidation film on the surface of magnesium alloy and aluminum alloy was comparatively analyzed during micro-arc oxidation.The results show that the connected part was integrally wrapped by the oxidation film after micro-arc oxidation for 10 min.The oxidation film connected with the two alloy substrates tightly and consisted of a compact layer and a loose layer.The oxidation film on the surface of magnesium alloy was composed of MgO and a small amount of silicates and fluoride.The oxidation film on the surface of aluminum alloy consisted of Al2O3 and a small amount of silicates.The microarc oxidation improved the corrosion potential of the magnesium alloy and aluminum alloy,reduced the corrosion potential difference between them and effectively alleviated the occurrence of galvanic corrosion.