Modification of plasma electrolytic coatings on aluminum alloys with corrosion inhibitors

Oleinik, S. V.; Руднев, В. С.; Kuzenkov, A. Yu.; Yarovaya, T. P.; Trubetskaya, L. F.; Недозоров, П. М.

doi:10.1134/s2070205113070113

Cited by 12 publications

(7 citation statements)

References 2 publications

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“…Since the oxide is chemically stable and its morphology is often compact, corrosion resistance is also enhanced [18][19][20]. In this regard, the incorporation of inhibitors or sealants into the coating leads to a further improvement [21][22][23]. The effect of the substrate alloy on the service properties of the PEO coatings has, however, been insufficiently addressed until now.…”

Section: Introductionmentioning

confidence: 99%

Plasma Electrolytic Oxidation of High-Strength Aluminium Alloys—Substrate Effect on Wear and Corrosion Performance

Sieber

Simchen

Morgenstern

et al. 2018

Metals

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Abstract:With the progress in materials science and production technology and the establishment of light-weight design in many fields of the industry, the application of light metals no longer requires only mechanical strength, but also a significant protection of the material against wear and corrosion. Hard and wear-resistant oxide coatings on aluminium are produced by plasma electrolytic oxidation (PEO). During PEO, a conversion of the aluminium substrate to a ceramic oxide takes place. While the role of strength-giving alloying elements like Cu, Mg/Si, Zn, and Zn/Cu on the PEO process has selectively been subject of investigation in the past, the significance of the alloy composition for the service properties of the coatings is still unknown. Therefore, the performance of PEO coatings produced on the widely used commercial high-strength alloys AlCu4Mg1 (EN AW-2024), AlMgSi1 (EN AW-6082), and AlZn5.5MgCu (EN AW-7075) is examined with regard to their behaviour in the rubber-wheel test according to ASTM G65 and the current density-potential behaviour of the substrates with undamaged and worn coatings in dilute NaCl solution. To give a reference to the unalloyed material the testings were carried out also on Al 99.5 (EN AW-1050) which was treated in an adjusted PEO process. Although differences in the conversion of intermetallic phases during PEO and the phase composition of the coatings on the various substrates are determined, the service properties are hardly depending on the alloying elements of the investigated aluminium materials. The wear rates in the rubber-wheel test are low for all the alloyed samples. The current density-potential curves show a decrease of the corrosion current density by approximately one order of magnitude compared to the bare substrate. Eventually, previous wear of the coatings does not deteriorate the corrosion behaviour. PEO layers on technically pure aluminum can resist the testing regimes if they are prepared in an electrolyte with an elevated silicate content and without additional hydroxide ions, during a longer process time.

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Section: Introductionmentioning

confidence: 99%

Plasma Electrolytic Oxidation of High-Strength Aluminium Alloys—Substrate Effect on Wear and Corrosion Performance

Sieber

Simchen

Morgenstern

et al. 2018

Metals

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“…Considering the application of corrosion inhibitors as electrolyte additives in other conversion coating processes like anodizing [8,9], their use in PEO process has also recently attracted attentions. Oleinka et al [10] investigated the effect of corrosion inhibitors in PEO process on aluminumbased alloys, They reported that existence of corrosion inhibitors raised hydrophobization. Another major advantage of PEO coating process in comparison with other conversional coating processes such as anodizing is that the former is environmentally friendly [11,12].…”

Section: Introductionmentioning

confidence: 98%

Tribological properties of PEO nanocomposite coatings on titanium formed in electrolyte containing ketoconazole

Sharifi

Mahmood

Darband

et al. 2016

Tribology International

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“…Because of the high porosity of the formed oxide layers, the incorporation of chemical substances by their impregnation into the sponge-like oxide is readily possible. In this way, many surface features, such as hydrophobicity [ 11 , 12 ], corrosion protection [ 13 , 14 , 15 ], or self-lubricating properties [ 16 ] can be attained by the final product. Some attempts have been made at incorporating layered double hydroxide (LDH) structures into the PEO porous oxide layers.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the incorporation of zeolite particles loaded with corrosion-inhibiting cerium ions into the PEO electrolytic bath was also exercised to give rise to a highly protective surface layer on an AZ31 magnesium alloy [ 20 ]. Many other approaches were tested, from the deposition of silica skeletons onto the surface of a PEO layer and their doping with an inhibitor solution [ 12 ], through loading of the PEO layer by immersion in a sodium hydroxide solution of inhibitor followed by drying at an elevated temperature [ 21 ], to the immersion of PEO layers in the solutions containing corrosion inhibitors at elevated temperature [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Corrosion Inhibitor-Modified Plasma Electrolytic Oxidation Coatings on 6061 Aluminum Alloy

et al. 2021

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There are many methods for incorporating organic corrosion inhibitors to oxide coatings formed on aluminum alloys. However, typically they require relatively concentrated solutions of inhibitors, possibly generating a problematic waste and/or are time-/energy-consuming (elevated temperature is usually needed). The authors propose a three-step method of oxide layer formation on 6061-T651 aluminum alloy (AAs) via alternating current (AC) plasma electrolytic oxidation (PEO), impregnation with an 8-hydroxyquinoline (8-HQ) solution, and final sealing by an additional direct current (DC) polarization in the original PEO electrolyte. The obtained coatings were characterized by scanning electron microscopy, roughness tests, contact angle measurements, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. Additionally, corrosion resistance was assessed by potentiodynamic polarization in a NaCl solution. Two types of the coating were formed (A—thicker, more porous at 440 mA cm−2; B—thinner, more compact at 220 mA cm−2) on the AA substrate. The 8-HQ impregnation was successful as evidenced by XPS. It increased the contact angle only for the B coatings and improved the corrosion resistance of both coating systems. Additional DC treatment destroyed superficially adsorbed 8-HQ. However, it served to block the coating pores (contact angle ≈ 80°) which improved the corrosion resistance of the coating systems. DC sealing alone did not bring about the same anti-corrosion properties as the combined 8-HQ impregnation and DC treatment which dispels the notion that the provision of the inhibitor was a needless step in the procedure. The proposed method of AA surface treatment suffered from unsatisfactory uniformity of the sealing for the thicker coatings, which needs to be amended in future efforts for optimization of the procedure.

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Modification of plasma electrolytic coatings on aluminum alloys with corrosion inhibitors

Cited by 12 publications

References 2 publications

Plasma Electrolytic Oxidation of High-Strength Aluminium Alloys—Substrate Effect on Wear and Corrosion Performance

Plasma Electrolytic Oxidation of High-Strength Aluminium Alloys—Substrate Effect on Wear and Corrosion Performance

Tribological properties of PEO nanocomposite coatings on titanium formed in electrolyte containing ketoconazole

Corrosion Inhibitor-Modified Plasma Electrolytic Oxidation Coatings on 6061 Aluminum Alloy

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