Al和Li对镁基体氧化膜成分及厚度影响

Effect of Al and Li on the composition and thickness of anodic coatings formed on Mg substrate

合金元素对氧化膜性能影响很大。分别恒流氧化了纯镁、AZ91HP和Mg-Li合金并测量了氧化膜成分及厚度。EDX分析表明，在Mg—Li合金上形成的氧化膜P含量最高（39．39％），AZ91HP上最低（35．88％）；膜厚测量结果为Al和Li分别使氧化膜厚度稍微减少和大大增加。Al和Li元素对氧化膜性能影响可以用Mg^2＋、Al^3＋和Li^＋移动速度不同以及MgO、Al2O3和Li2O的PBR（Pilling—Bedweorth ratio）值不同来解释。

Alloying elements have major effects on coating properties. In this paper, pure magnesium, AZ91HP and Mg-Li were anodized under constant current mode and the compositions and thickness of anodic coating were separately detected. Analysis by EDX, the phosphorus content of anodic coating on Mg-Li was the highest （39.39%） and that on AZ91HP the lowest （35.88%）. The measuring of coating thickness showed that addition of aluminum and lithium resulted in slight decrease and considerable improvement in coating thickness, respectively. The effects of aluminum and lithium on coating properties could be explained by the difference of moving speeds of Mg^2＋, Al^3＋ and Li^＋ and PBRs （Pilling-Bedweorth ratios） of MgO, Al2O3 and Li2O.