Formation of layered double hydroxides film on AA2099-T83 Al-Cu-Li alloy and its effect on corrosion resistance
By Liang, Z.; Ma, Y.; Li, K.; Liao, Y.; Yang, B.; Liu, L.; Zhu, P.
Published in Surface and Coatings Technology
2019
Abstract
A layered double hydroxides (LDH) film was formed on AA2099-T83 Al-Cu-Li alloy in a mixed solution containing 0.05 M Zn (NO3)2·6H2O and 0.3 M NH4NO3 at 75 °C. Field emission scanning electron microscope, ultramicrotomy and electrochemical impedance spectroscopy were employed to characterize the structure and corrosion properties of the alloy after different treatments. It was found that the LDH film preferred to form on coarse intermetallic particles; the thickness of the LDH film and its corrosion resistance initially increased with increasing preparation time (up to 12 h); micro-cracks then developed in the LDH film after 24 h formation, leading to deterioration of its corrosion resistance; loading vanadate ions significantly improved the long-term corrosion resistance of the LDH film. It is suggested that the LDH film is a promising substitute for anodizing treatment of Al-Cu-Li alloys.