scholarly journals Surface Modification of Aluminum 6061-O Alloy by Plasma Electrolytic Oxidation to Improve Corrosion Resistance Properties

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Dmitry V. Dzhurinskiy ◽  
Stanislav S. Dautov ◽  
Petr G. Shornikov ◽  
Iskander Sh. Akhatov
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
High Strength ◽  
Electrolytic Oxidation ◽  
Coating Layers ◽  
Plasma Electrolytic ◽  
High Strength Aluminum Alloys

In the present investigation, the plasma electrolytic oxidation (PEO) process was employed to form aluminum oxide coating layers to enhance corrosion resistance properties of high-strength aluminum alloys. The formed protective coating layers were examined by means of scanning electron microscopy (SEM) and characterized by several electrochemical techniques, including open circuit potential (OCP), linear potentiodynamic polarization (LP) and electrochemical impedance spectroscopy (EIS). The results were reported in comparison with the bare 6061-O aluminum alloy to determine the corrosion performance of the coated 6061-O alloy. The PEO-treated aluminum alloy showed substantially higher corrosion resistance in comparison with the untreated substrate material. A relationship was found between the coating formation stage, process parameters and the thickness of the oxide-formed layers, which has a measurable influence on enhancing corrosion resistance properties. This study demonstrates promising results of utilizing PEO process to enhance corrosion resistance properties of high-strength aluminum alloys and could be recommended as a method used in industrial applications.

scholarly journals Fabrication and Characterization of Ceramic Coating on Al7075 Alloy by Plasma Electrolytic Oxidation in Molten Salt

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 993
Author(s):  
Alexander Sobolev ◽  
Tamar Peretz ◽  
Konstantin Borodianskiy
Keyword(s):  
Corrosion Resistance ◽  
Molten Salt ◽  
Plasma Electrolytic Oxidation ◽  
Ceramic Coating ◽  
Electrochemical Impedance ◽  
Current Frequency ◽  
Electrolytic Oxidation ◽  
Fabrication And Characterization ◽  
Plasma Electrolytic

The fabrication of a ceramic coating on the metallic substrate is usually applied to achieve the improved performance of the material. Plasma electrolytic oxidation (PEO) is one of the most promising methods to reach this performance, mostly wear and corrosion resistance. Traditional PEO is carried out in an aqueous electrolyte. However, the current work showed the fabrication and characterization of a ceramic coating using PEO in molten salt which was used to avoid disadvantages in system heating-up and the formation of undesired elements in the coating. Aluminum 7075 alloy was subjected to the surface treatment using PEO in molten nitrate salt. Various current frequencies were applied in the process. Coating investigations revealed its surface porous structure and the presence of two oxide layers, α-Al2O3 and γ-Al2O3. Microhardness measurements and chemical and phase examinations confirmed these results. Potentiodynamic polarization tests and electrochemical impedance spectroscopy revealed the greater corrosion resistance for the coated alloy. Moreover, the corrosion resistance was increased with the current frequency of the PEO process.

scholarly journals TiO2Deposition on AZ31 Magnesium Alloy Using Plasma Electrolytic Oxidation

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Leon White ◽  
Youngmi Koo ◽  
Yeoheung Yun ◽  
Jagannathan Sankar
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Protective Layer ◽  
Az31 Magnesium Alloy ◽  
Treatment Technique ◽  
Functional Coating ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Plasma electrolytic oxidation (PEO) has been used in the past as a useful surface treatment technique to improve the anticorrosion properties of Mg alloys by forming protective layer. Coatings were prepared on AZ31 magnesium alloy in phosphate electrolyte with the addition of TiO2nanoparticles using plasma electrolytic oxidation (PEO). This present work focuses on developing a TiO2functional coating to create a novel electrophotocatalyst while observing the surface morphology, structure, composition, and corrosion resistance of the PEO coating. Microstructural characterization of the coating was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) followed by image analysis and energy dispersive spectroscopy (EDX). The corrosion resistance of the PEO treated samples was evaluated with electrochemical impedance spectroscopy (EIS) and DC polarization tests in 3.5 wt.% NaCl. The XRD pattern shows that the components of the oxide film include Mg from the substrate as well as MgO and Mg2TiO4due to the TiO2nanoparticle addition. The results show that the PEO coating with TiO2nanoparticles did improve the corrosion resistance when compared to the AZ31 substrate alloy.

Industrial Application in 2014 T6 Aluminum Alloys Having High Corrosion and Weather Resistant by Anionic Resin Coating with Mirror Luster

2007 ◽  
Vol 561-565 ◽  
pp. 127-130
Author(s):  
M. Hara ◽  
K. Matsuda ◽  
T. Iwai ◽  
M. Kihara ◽  
W. Yamauchi ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Industrial Application ◽  
High Strength ◽  
Treatment Technology ◽  
High Corrosion ◽  
Claim Number ◽  
Weather Resistance ◽  
High Strength Aluminum Alloys

A new surface treatment technology for the aluminum alloys that exhibits not only high corrosion and weather resistance but also good mirror luster has been developed. By performing electrolytic permeation, the improved corrosion resistance and weather resistance while maintaining a high mirror luster was achieved for an aluminum alloy A2014-T6. The high strength aluminum alloys featuring high corrosion and weather resistance have been available for industrial products. Then the claim number of the products by A2014 T6 aluminum alloy has been reduced sharply to almost zero level in comparison with a past. A few applications and the development of the processing in industrial scale in A2014 T6 aluminum alloy will be presented.

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

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 619
Author(s):  
Maciej Sowa ◽  
Marta Wala ◽  
Agata Blacha-Grzechnik ◽  
Artur Maciej ◽  
Alicja Kazek-Kęsik ◽  
...  
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Photoelectron Spectroscopy ◽  
Plasma Electrolytic Oxidation ◽  
Step Method ◽  
Corrosion Properties ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

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.

scholarly journals Corrosion resistance of AZ31 magnesium alloy treated by plasma electrolytic oxidation

2019 ◽  
Vol 63 (2) ◽  
pp. 65-71
Author(s):  
D. Kajánek ◽  
B. Hadzima ◽  
J. Tkacz ◽  
J. Pastorková ◽  
M. Jacková ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Az31 Magnesium Alloy ◽  
Potentiodynamic Curves ◽  
Coating Morphology ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Dc Current

Abstract The coating prepared by plasma electrolytic oxidation (PEO) was created on AZ31 magnesium alloy surface with the aim to evaluate its effect on corrosion resistance. The DC current was applied on the sample in solution consisted of 10 g/l Na3PO4·12H2O and 1 g/l KOH. Additional samples were prepared with 2 and 4 minutes of preparation to observe evolution of the PEO coating. Morphology of the coatings was evaluated by scanning electron microscopy and chemical composition was examined by EDX analysis. Electrochemical characteristic were measured by potentiodynamic polarization tests and electrochemical impedance spectroscopy in 0.1 M NaCl at the laboratory temperature. Obtained data were presented in form of potentiodynamic curves and Nyquist diagrams. Results of analysis showed that plasma electrolytic oxidation coating positively influence corrosion resistance of AZ31 magnesium alloy in chosen corrosive environment.

scholarly journals Impact of Processing Parameters in Plasma Electrolytic Oxidation (PEM) on Corrosion Resistance of Magnesium Alloy Type AZ91

2021 ◽  
Author(s):  
Talal Aljohani ◽  
Sami Aljadaan ◽  
Meteb Bin Rubayan ◽  
Fuad Khoshnaw
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Duty Cycle ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Processing Parameters ◽  
Coated Sample ◽  
Alloy Type ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

This study aims to investigate the effect of the processing parameters in plasma electrolytic oxidation (PEO) on the corrosion resistance of magnesium alloy type AZ91. The PEO coatings were prepared on the samples using alkaline-based electrolyte. Both unipolar and bipolar, different frequencies and duty cycles were applied. Corrosion tests, using potentiodynamic polarisation (PDP), linear and cyclic, and electrochemical impedance spectroscopy (EIS) techniques, were applied on the as-received and PEO coated samples. Scanning electron microscopy was used to investigate the surface morphology, e.g. micropores, as well as to measure the thickness of the coated layer with changing the processing parameters. The results show that the size of micropores is interrelated to the duty cycle percentage and current polarities, as the higher frequency causes thinner coating layers, with fewer micropores, consequently higher corrosion resistance. In addition, increasing the duty cycle, a denser and more compact coating was obtained. The XRD results showed missing peak of the α-Mg phase in a PEO coated sample using Bipolar, the highest frequency (1666 Hz) and the highest duty cycle (66.6%). The mils per year calculations showed that the PEO coated have lower corrosion rate by at least 8 times than the as-received alloy.

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