【摘要】 为提高AZ31镁合金的耐蚀性,对高能微弧火花合金化技术制备的Al-Y涂层进行研究。涂层的耐蚀性采用极化曲线测试和浸泡腐蚀实验进行评价。涂层的结构采用金相、扫描电镜及其附带的能谱仪、物相衍射来表征。合金化过程中表面出现“喷溅特征”。实验得到均匀、致密的涂层。涂层厚度为22.5~30μm,晶粒尺寸为1~1.5μm。涂层由Al、Mg17Al12和Al3Y金属间化合物组成。同原AZ31基材相比,Al-Y涂层的耐蚀性较高。浸泡实验表明Al-Y上形成的表面膜比AZ31上形成的表面膜在3.5wt%NaCl溶液中更能提供有效的保护。经初步分析,涂层中的Al和Y对改善耐蚀性均有益。更多还原

【Abstract】 An attempt was made to improve the corrosion resistance of a AZ31 magnesium alloy modified by high-energy micro-arc alloying（HEMAA） technique.A 3H-ES HEMAA machine was employed to deposit Al-Y coating layer on AZ31 magnesium alloy to improve the corrosion resistance.The corrosion resistance was evaluated using dynamic-potential polarization and long term immersion tests.The microstructure of the Al-Y coating was examined using optical microscope（OM） and scanning electron microscope（SEM） with energy dispersive spectroscope（EDS）,X-ray diffraction（XRD）.Spattering pattern appears on the surface during the HEMAA process.A fully dense and uniform coating is obtained.The coating has a typical thickness of 25～32.5μm with grain size of 1～1.5μm.The examination of the coating shows a complex microstructure,consisting of Al,Mg₁₇Al₁₂ and Al₃Y.The coating investigated exhibits improved corrosion resistance compared with that of AZ31 alloy substrate.Immersion tests reveal that the surface layers formed on Al-Y coating provide a better protection than that of the layers formed on AZ31 alloy in 3.5wt%NaCl solution.Based on preilimary analysis,the presence of Y and Al is beneficial for improving the corrosion resistance of the coating.更多还原