Al合金铈盐转化膜缓蚀机理研究

Ce盐作为一种环境友好的Al合金缓蚀剂日益受到重视 ,但缓蚀机理还不很清楚 .本文应用自行研制的扫描微参比电极技术 (SMRE) ,原位测量经CeCl3处理和未处理过的 2 0 2 4 T3Al合金表面微区电位分布 ,并用扫描电子显微镜 (SEM )和X 射线能量散射谱 (EDS)表征样品形貌特征 ,结合其它电化学技术 ,对Ce盐缓蚀机理作了深入探讨 .结果表明 ,经Ce盐处理的Al合金表面可形成一层不均匀分布的转化膜 ,抑制了O2 和电子传输 ,表现为一种优良的阴极缓蚀特性

An Investigation of Inhibition Mechanism of Cerium for Aluminum Alloy 2024-T3

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.