Electrochemical characterization of anti-corrosion coatings formed on 6061 aluminum alloy by plasma electrolytic oxidation in the corrosion inhibitor-enriched aqueous solutions. (20th August 2022)

• Record Type: Journal Article
• Authors: Sowa, Maciej; Olesiński, Aleksander; Szumski, Bartosz; Maciej, Artur; Bik, Maciej; Jeleń, Piotr; Sitarz, Maciej; Simka, Wojciech
• Is Part Of: Electrochimica acta. Volume 424(2022)
• Publication Date: 2022-08-20
• Subjects: Aluminum alloy -- Plasma electrolytic oxidation -- Corrosion inhibitor -- Electrochemical impedance spectroscopy -- Potentiodynamic polarization; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2022.140652
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: PEO in the borate bath brought more anti-corrosion effect than in the silicate bath. The PEO oxide coatings were modified with the use of corrosion inhibitors (CIs). The single-step method was the addition of 0.1 g L −1 of a CI to the Si or B bath. The sequential method was the dipping of the coating in a CI solution and DC PEO. Mullite, α - and γ -Al2 O3 were detected in the PEO oxide coatings. Acrylic acid was the most effective CI in both single-step and sequential methods. Abstract: The 6061 aluminum alloy was surface-treated by plasma electrolytic oxidation (PEO) in silicate- and borate-based electrolyte systems. The authors attempted to incorporate selected corrosion inhibitors (8-hydroxyquinoline, 2-mercaptobenzothiazole, poly(acrylic acid) with molecular weights of 1800 and 450, 000 g mol −1, and acrylic acid) into the oxide coating to provide long-lasting protection of the substrate. These inhibitors were either added directly to the electrolyte for the treatment or loaded into the coatings through a sequential PEO procedure. Electrochemical corrosion tests showed that acrylic acid-modified coatings provided the best protection. In general, of the two methods, the sequential PEO gave more reproducible anti-corrosion effects. Graphical abstract: Image, graphical abstract