关键词: ＡＡ２０９９Ｔ８３, ＬｉＡｌＬＤＨ, 草酸锂, 腐蚀防护, 自修复

Abstract: The 3rd generation aluminum-lithium alloy is widely used in aerospace industry to realize lightweight manufacturing of aircraft. In this paper, the process of in-situ preparation of lithium salt conversion coating in lithium oxalate (Li2C2O4) aqueous solution was explored to improve the corrosion resistance of AA2099-T83 alloy. The microstructure and composition of the conversion coating were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion resistance of the coating was studied by electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). The results showed that the concentration and temperature of the solution had a significant effect on the corrosion resistance of the conversion coating. The corrosion resistance increased with the increase of temperature and decreased with the increase of concentration. The conversion coating prepared in 0.01 M Li2C2O4 solution at 70 ℃ had the best corrosion resistance. The present work suggests that the Li-Al-LDH conversion coating on AA2099-T83 aluminum-lithium alloy has self-healing capacity without uploading any corrosion inhibitors. The Li-Al-LDH conversion coating can reduce the sensitivity of the alloy to localized corrosion and also inhibit the steady-state propagation of corrosion and, therefore, can be used as the primer of anti-corrosion coating for aluminum-lithium alloys.