关键词: 镁合金, 离子液体, 电镀, 铝, 耐蚀性

Abstract: Electrodeposition of a metallic aluminum on a magnesium alloy in acidic aluminum chloride-1-ethyl-3-methylimidazolium chloride ionic liquids(AlCl3-EMIC) was investigated.The effects of current density and AlCl3 content in the ionic liquid on the electrodeposition behavior were studied.The results showed that aluminum could be successfully electrodeposited on the AZ91D substrate.At-0.2 V,the ionic liquid containing 60 m/o AlCl3 was optimum for Al electrodeposition.The current efficiency was higher if electrodeposition was performed at a lower applied current density.The existence of Al coating could caused a substantial increase in open circuit potential,reducing the susceptibility of Mg alloy to corrosion.The results of electrochemical impedance spectroscopy showed that Al coating could cause the increase in the polarization resistance of a bare Mg alloy from 470~510 Ω·cm2 to 5200 Ω·cm2 in 3.5%(by mass) NaCl solution.Furthermore,the results of potentiodynamic polarization measurements showed that Al-coated Mg alloy could be passivated with the passive current density as low as 5×10-5 A/cm2.

Key words: magnesium alloy, ionic liquid, electrodeposition, aluminum, corrosion