铝合金微弧氧化膜纳米TiO2掺杂机理研究

Mechanism Research of Nano TiO2 Doping Micro-arc Oxidation Coating on Aluminum Alloy

摘要:

为了研究掺杂纳米TiO₂对铝合金微弧氧化成膜作用机理,在不同浓度纳米TiO₂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Ti、Al、O等元素含量,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TiO₂表面电荷,建立了掺杂改性模型。结果表明,加入纳米TiO₂后,氧化初期电压随TiO₂添加量增加逐渐升高、5min后电压逐渐降低；氧化膜表面孔洞数量和尺寸减小,成膜效率、膜层致密度和表面疏松层硬度提高。纳米TiO₂在氧化膜表面均匀分布,截面不均匀分布。氧化膜主要由γ-Al₂O₃、Mullite和少量Si组成。

Abstract:

In order to research the mechanism of nano TiO₂ doping effect on micro-arc oxidation coating formed on aluminum alloy, it was treated by using micro-arc oxidation in different concentration of nano TiO₂ electrolyte. Surface morphologies,Ti, Al,O and elements content, 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 nano TiO₂ in electrolyte were measured. The doping modification model was established in this paper. The results show that the oxidation voltage were raised at initial stage, and then declined after 5minutes.The numbers and sizes of hole on oxidation coating surface decreased, formation efficiency and compactness of coating, and the hardness of surface porosity coating increased. The nano TiO₂ was distributed homogeneous on oxidation coating surface, and inhomogeneous on cross-section. Oxidation coating was mainly composed by γ-Al₂O₃, mullite and little Si phase.