Abstract Anodic aluminum oxidation (AAO) process on sputtered-Al film to form an oxide coating as an anticorrosion layer on AZ91D magnesium alloy was performed. The cross-sectional scanning electron microscope images showed an increase on the thickness of anodized oxide layer with increasing oxidation duration. By X-ray photoelectron spectroscopy and X-ray diffraction analyses, the anodized alumina layer had an amorphous structure, where the chemical composition is mainly composed of aluminum oxide. From the results of anticorrosion test, the higher charge transfer resistance of oxide layer was obtained for all AAO specimens by electrochemical impedance spectroscopy, as compared to the raw AZ91D substrate. In addition, the potentiodynamic polarization measurement showed that the specimen with 15 min anodizing treatment had the lower corrosion current density (0.29 μA/cm2), and the higher protection efficiency (99.64 %). These results proved that Al oxide/Al bi-layer composite passive film on AZ91D alloys is significantly improved the corrosion resistance behaviors and the optimal parameter for AAO process is 15 min.

中文翻译：

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溅射和阳极氧化铝一体化工艺在镁合金表面形成铝复合钝化膜

摘要 对溅射铝膜进行阳极铝氧化(AAO)工艺，在AZ91D镁合金上形成氧化膜作为防腐层。横截面扫描电子显微镜图像显示阳极氧化层的厚度随着氧化持续时间的增加而增加。通过 X 射线光电子能谱和 X 射线衍射分析，阳极氧化铝层具有无定形结构，其中化学成分主要由氧化铝组成。从防腐测试的结果来看，与原始 AZ91D 基板相比，所有 AAO 样品的氧化层电荷转移电阻都通过电化学阻抗谱获得更高。此外，动电位极化测量表明，阳极氧化处理15分钟的试样具有较低的腐蚀电流密度（0.29 μA/cm2）和较高的保护效率（99.64 %）。这些结果证明AZ91D合金上的Al氧化物/Al双层复合钝化膜显着改善了耐腐蚀性能，AAO工艺的最佳参数为15 min。