关键词: 铈盐, Al合金, 缓蚀剂, 扫描微电极技术

Abstract: Cerium compounds are promising inhibitors for aluminum alloy. However, the inhibition mechanism is not very clear. Scanning microreference electrode(SMRE)technique was used to probe the potential imaging of Al 2024 T3 in NaCl and CeCl 3 solution. The results of SMRE showed that in NaCl solution a severe localized corrosion occurred on the surface of Al 2024 specimen at once and maintained for a long time. The corrosion activity of Al alloy in CeCl 3 decreased with immersion time and disappeared finally. Additionally, the competition of inhibition and aggression between Ce 3+ and Cl - on Al alloy was in situ monitored in CeCl 3 by SMRE. The corrosion of Al 2024 treated with CeCl 3 did not occur until it was immersed in 0.01 mol/L NaCl for 12.5 h. Polarization curves and EIS also showed the resistance of the treated Al alloy to localized corrosion apparently raised. Scanning electron microscopy (SEM) imaging showed that the Ce conversion films covered on the alloy surface were non uniform, and most Ce concentration located on the Cu rich particles which acted as cathodic sites generally. The Ce conversion films inhibited the localized corrosion of Al 2024 by blocking the transmission of O 2 and elctron to the second phase particles.