Al2O3微粉添加量对镁合金微弧氧化膜特性影响研究

Effects of Al2O3Micro Powder Additive Amount on Characteristics of Micro-arc Oxidation Coating Formed on Magnesium Alloy

摘要:

为了研究添加Al₂O₃微粉对AZ31A镁合金微弧氧化膜特性影响,在不同浓度Al₂O₃微粉电解液中对其进行了微弧氧化处理。利用扫描电镜(SEM)观察微弧氧化膜形貌,能谱仪(EDS)分析了膜层表面Ca、Mg、O、Al元素分布,X射线衍射仪(XRD)分析了相组成,测定了膜厚、硬度和氧化液中Al₂O₃表面电荷,讨论了掺杂改性机理。结果表明,加入Al₂O₃微粉后,氧化电压随Al₂O₃添加量增加先增加后降低；氧化膜表面孔洞数量和尺寸减小,膜层表面Ca元素分布逐渐减少,成膜效率降低,膜层致密度和表面疏松层硬度提高,氧化膜主要由MgO和MgO₄等相组成。

Abstract:

In order to research the effects of Al₂O₃ micro powder additive amount on characteristics of micro-arc oxidation coating formed on AZ31A magnesium alloy, it was treated by using micro-arc oxidation in different concentration of Al₂O₃ micro powder electrolyte. Surface morphologies, Ca, Mg, O and Al elements distribution, phase composition of micro-arc oxidation coating were analyzed by SEM, EDS and XRD. Thickness and hardness of micro-arc oxidation coating and surface charge of Al₂O₃ micro powder in electrolyte were measured. The doping modification mechanism was discussed in this paper. The results show that the oxidation voltage was raised firstly and then declined gradually while Al₂O₃ micro powder amount increasing. The numbers and sizes of hole and distribution of Ca element on oxidation coating surface and formation efficiency decreased, compactness of coating, and the hardness of surface porosity coating increased. Oxidation coating was mainly composed by MgO and MgO₄ phase.