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利用扫描电镜(SEM)、X射线衍射(XRD)等分析手段,研究Mg-11Gd-1Y-0.5Zn合金微弧氧化陶瓷层的生长规律,分析微弧氧化膜层相结构及不同生长阶段的耐蚀性。结果表明,在微弧氧化初期,膜层生长遵循直线规律,为典型的电化学极化控制的阳极沉积阶段;随处理时间的延长及膜层增厚,膜层生长符合抛物线规律,属微弧氧化阶段,较氧化初期相比,生长速率慢;在弧光放电阶段,抛物线斜率增大,疏松层增厚,生长速率有所提高。微弧氧化疏松层主要以MgSiO3为主,致密层以MgO为主;微弧氧化各阶段,膜层耐蚀性随氧化时间增长而提高,到弧光放电阶段,耐蚀性有所降低。在7～12min时,膜层具有较好的耐蚀性。
The growth of the MAO-Mg-11Gd-1Y-0.5Zn alloy micro-arc oxidation ceramic coating was studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The phase structure of microarc oxidation coatings and the resistance to different growth stages Erosive. The results show that in the initial stage of micro-arc oxidation, the growth of the film follows the linear rule and is typical of the anodic deposition stage controlled by electrochemical polarization. The growth of the film conforms to the parabolic law with the extension of the processing time and the thickening of the film, In the oxidation stage, the growth rate is slower than that in the initial stage of oxidation. During the arc discharge stage, the slope of the parabola increases, the loose layer thickens and the growth rate increases. The micro-arc oxidation loose layer is dominated by MgSiO3 and the dense layer is dominated by MgO. The corrosion resistance of the coatings increases with the increase of oxidation time in each stage of micro-arc oxidation, and decreases to the stage of arc discharge. In 7 ~ 12min, the film has good corrosion resistance.