Impact of rare earth compounds on corrosion of aluminum alloy (AA6061) in the marine water environment

摘要

The impact of rare earth compounds (CeCl3 and Ce-2(SO4)(3)) on the corrosion inhibition of aluminum alloy (AA6061) in 3.5% NaCl solution was elucidated using polarization, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS) and complemented with EDX and SEM examination. The addition of either CeCl3 or Ce-2(SO4)(3) to the blank chloride solution, decreases the corrosion current and causes a widening of the passive potential range between corrosion potential (E-corr) and pitting potential (E-pit). The data confirmed that CeCl3 and Ce-2(SO4)(3) act as corrosion inhibitors. It was found that the inhibition performance of Ce-2(SO4)(3) are higher than that of CeCl3. In the presence of Ce-2(SO4)(3) and CeCl3, the AA6061 surface is well protected, in which the surface of AA6061 was smoother and the corroded areas obviously diminished. The results suggest that the existence of Ce2O3/Ce(OH)(3) conversion coat on the electrode surface enhances the charge and mass barrier leading to the reduction in corrosion rates of the AA6061 alloy. (C) 2019 Elsevier B.V. All rights reserved.