Electrodeposition of Al on Magnesium alloy - Engineering Information Institute

Articles

Electrodeposition of Al on Magnesium alloy [SCET 2017]
Author(s)
Wen-Ta Tsai
ABSTRACT
Al coating on magnesium (Mg) alloy with a large dimension of surface area was attempted by employing ionic liquid electrodeposition. The electrolyte used was AlCl3-EMIC ionic liquid with a molar ratio of 2:1. The effects of additive and electrodeposition potential on the properties of Al coating were focused. The surface morphology of Al coating was examined by a scanning electron microscope (SEM), while its crystal structure was analyzed by X-ray diffraction. The corrosion performances of the Mg alloy with and without Al coating were evaluated by conducting various electrochemical measurements in 3.5 wt% NaCl solution. The experimental results showed that the surface roughness of the coating could be improved by proper surface pretreatment and electrolyte composition adjustment. The results of potentiodynamic polarization tests in 3.5 wt% NaCl solution showed that the corrosion resistance of the Mg alloy studied could be substantially improved by Al coating. The passivation behavior of Al coating depended on the electrodeposition potential applied. A maximum polarization resistance of 86500 Ω-cm2 was determined by electrochemical impedance spectroscopy (EIS), which was about two order of magnitude higher than that of the bare Mg alloy studied.
KEYWORDS
Electrodeposition, Al, Magnesium alloy
References