Inhibition of corrosion of Al 6061, aluminum, and an aluminum-copper alloy in chloride-free aqueous media. Part 2: Behavior in basic solutions
Abstract
Electrochemical characteristics of Al 6061 (UNS A96061), Al and an Al-Cu alloy were investigated in aqueous solutions. Inhibition of the corrosion processes in basic solutions was studied using electrochemical impedance spectroscopy (EIS) and polarization techniques. Among a series of inhibitors, molybdate (MoO{sub 4}{sup 2{minus}}) and dichromates (Cr{sub 2}O{sub 7}{sup 2{minus}}) were found effective in passivating the metal or alloy surface. The high inhibition action of Cr{sub 2}O{sub 7}{sup 2{minus}} was traced and discussed. X-ray photoelectron spectroscopy (XPS) of the different electrode materials revealed the presence of Cu peaks on the Al-Cu alloy surface. Immersion of the different electrodes in basic solutions containing the same concentration of Cr{sub 2}O{sub 7}{sup 2{minus}}, MoO{sub 4}{sup 2{minus}}, and sulfate (SO{sub 4}{sup 2{minus}}) anions did not show characteristic peaks of Cr, Mo, or S, which meant the surface layer consisted mainly of aluminum oxide (Al{sub 2}O{sub 3}). Depth profiling experiments up to 6.0-nm thickness showed the Cu peaks of the Al-Cu alloy appeared after etching and that Mo was incorporated in the surface film. The presence of Cu on the Al-Cu surface initiated flawed regions, identified by scanning electron microscopy, which were responsible for increased corrosion rates of this alloy. Effectiveness of the dichromate asmore »
- Authors:
-
- Univ. of Kuwait, Safat (Kuwait)
- Publication Date:
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 669825
- Resource Type:
- Journal Article
- Journal Name:
- Corrosion
- Additional Journal Information:
- Journal Volume: 54; Journal Issue: 5; Other Information: PBD: May 1998
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; CORROSION PROTECTION; ALUMINIUM; ALUMINIUM ALLOYS; COPPER ALLOYS; ELECTROCHEMISTRY; CORROSION INHIBITORS; AQUEOUS SOLUTIONS; FILMS; PASSIVATION; SPECTROSCOPY
Citation Formats
Al-Kharafi, F M, and Badawy, W A. Inhibition of corrosion of Al 6061, aluminum, and an aluminum-copper alloy in chloride-free aqueous media. Part 2: Behavior in basic solutions. United States: N. p., 1998.
Web. doi:10.5006/1.3284865.
Al-Kharafi, F M, & Badawy, W A. Inhibition of corrosion of Al 6061, aluminum, and an aluminum-copper alloy in chloride-free aqueous media. Part 2: Behavior in basic solutions. United States. https://doi.org/10.5006/1.3284865
Al-Kharafi, F M, and Badawy, W A. 1998.
"Inhibition of corrosion of Al 6061, aluminum, and an aluminum-copper alloy in chloride-free aqueous media. Part 2: Behavior in basic solutions". United States. https://doi.org/10.5006/1.3284865.
@article{osti_669825,
title = {Inhibition of corrosion of Al 6061, aluminum, and an aluminum-copper alloy in chloride-free aqueous media. Part 2: Behavior in basic solutions},
author = {Al-Kharafi, F M and Badawy, W A},
abstractNote = {Electrochemical characteristics of Al 6061 (UNS A96061), Al and an Al-Cu alloy were investigated in aqueous solutions. Inhibition of the corrosion processes in basic solutions was studied using electrochemical impedance spectroscopy (EIS) and polarization techniques. Among a series of inhibitors, molybdate (MoO{sub 4}{sup 2{minus}}) and dichromates (Cr{sub 2}O{sub 7}{sup 2{minus}}) were found effective in passivating the metal or alloy surface. The high inhibition action of Cr{sub 2}O{sub 7}{sup 2{minus}} was traced and discussed. X-ray photoelectron spectroscopy (XPS) of the different electrode materials revealed the presence of Cu peaks on the Al-Cu alloy surface. Immersion of the different electrodes in basic solutions containing the same concentration of Cr{sub 2}O{sub 7}{sup 2{minus}}, MoO{sub 4}{sup 2{minus}}, and sulfate (SO{sub 4}{sup 2{minus}}) anions did not show characteristic peaks of Cr, Mo, or S, which meant the surface layer consisted mainly of aluminum oxide (Al{sub 2}O{sub 3}). Depth profiling experiments up to 6.0-nm thickness showed the Cu peaks of the Al-Cu alloy appeared after etching and that Mo was incorporated in the surface film. The presence of Cu on the Al-Cu surface initiated flawed regions, identified by scanning electron microscopy, which were responsible for increased corrosion rates of this alloy. Effectiveness of the dichromate as a corrosion inhibitor for these materials resulted from its powerful oxidizing properties, which led to formation of a stable passive film.},
doi = {10.5006/1.3284865},
url = {https://www.osti.gov/biblio/669825},
journal = {Corrosion},
number = 5,
volume = 54,
place = {United States},
year = {Fri May 01 00:00:00 EDT 1998},
month = {Fri May 01 00:00:00 EDT 1998}
}