Abstract
Abstract In order to overcome the problem of the corrosion resistance of AZ31 magnesium alloy, the nanocrystalline Al 2 O 3 film was deposited on AZ31 magnesium alloy by double cathode glow-discharge plasma technique. The microstructure, chemical composition and elemental chemical state of the sputter-deposited nanocrystalline Al 2 O 3 film were analyzed by means of scanning electron microscopy equipped with an energy dispersive spectroscope, X-ray diffraction), transmission electron microscope and X-ray photoelectron spectroscopy. The results indicated that the sputter-deposited nanocrystalline Al 2 O 3 film consisted of single θ-Al 2 O 3 phase with average grain size about 60 nm. The hardness and the elastic modulus of the as-deposited nanocrystalline Al 2 O 3 film were about 17.21 GPa and 217 GPa measured by nanoindentation instrument, respectively. The corrosion behavior of the sputter-deposited nanocrystalline Al 2 O 3 film in 3.5%NaCl solution was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. The amount of porosity for the sputter-deposited nanocrystalline Al 2 O 3 film calculated by two electrochemical methods was equal to 0.0086% and 0.168%, respectively. The sputter-deposited nanocrystalline Al 2 O 3 film exhibited excellent corrosion resistance, which was attributed to its dense enough structure to prevent magnesium alloy from corrosion in aggressive solutions.
Published Version
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