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Effect of NaAlO 2 sealing on corrosion resistance of 2024 aluminum alloy anodized film
Author(s) -
Yang Yingshuo,
Cheng Jie,
Liu Shengli,
Wang Haiyun,
Dong Peng
Publication year - 2019
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201810327
Subject(s) - anodizing , corrosion , materials science , alloy , dielectric spectroscopy , scanning electron microscope , metallurgy , x ray photoelectron spectroscopy , aluminium , oxide , oxalic acid , electrochemistry , chemical engineering , composite material , inorganic chemistry , electrode , chemistry , engineering
In order to effectively improve the corrosion resistance of aluminum alloys, anodic oxidation technique was used to generate the oxide film. Sealing after anodization is an important step to improve the corrosion resistance of aluminum alloys. In this paper, sealing effect of NaAlO 2 solution on the oxalic acid anodized aluminum alloy was studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and X‐ray photoelectron spectroscopy (XPS). Experimental results show that unsealed anodized aluminum alloys display a porous structure and have poor corrosion resistance but the pores are filled and the corrosion resistance of the sample is significantly improved when anodized aluminum alloy was immersed in 0.2 m/L NaAlO 2 solution with pH of 7 for 5 min at 85 °C. Moreover, the anodized aluminum alloy with NaAlO 2 sealing exhibited better corrosion resistance compared to the hydrothermally sealed sample, because of the formation of more AlOOH in NaAlO 2 sealing treatment.