Electrochemical impedance and morphological studies into of initial stages of Plasma Electrolytic Oxidation of magnesium alloy

2021 ◽  
Author(s):  
Veta R. Aubakirova ◽  
Ruzil G. Farrakhov ◽  
Ekaterina S. Mescheryakova ◽  
Evgeny V. Parfenov
Keyword(s):  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Morphological Studies ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

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.

Comparison of Electrochemical and Chemical Corrosion Behavior of MRI 230D Magnesium Alloy with and without Plasma Electrolytic Oxidation Treatment

2015 ◽  
Vol 364 ◽  
pp. 27-34
Author(s):  
Barbara Kazanski ◽  
Alex Lugovskoy ◽  
Ohad Gaon ◽  
Michael Zinigrad
Keyword(s):  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Corrosion Behavior ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Weight Ratio ◽  
Open Circuit ◽  
Chemical Corrosion ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Magnesium is one of the lightest metals and magnesium alloys have quite special properties, interest to which is continuously growing. In particular, their high strength-to-weight ratio makes magnesium alloys attractive for various applications, such as transportation, aerospace industryetc. However, magnesium alloys are still not as popular as aluminum alloys, and a major issue is their corrosion behavior.The present research investigated the influence of the PEO treatment on the corrosion behavior of MRI 230M magnesium alloy. Plasma electrolytic oxidation (PEO) of an MRI 230M alloy was accomplished in a silicate-base electrolyte with KF addition using an AC power source.The corrosion behavior of both treated and untreated samples was evaluated by open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS), linear polarization tests, linear sweep voltammetry (Tafel extrapolation) and chemical methods, such as mass loss and hydrogen evolution, in neutral 3.0 wt% NaCl solution.According to the tests results, PEO process can affect the corrosion resistance of MRI 230M magnesium alloy, though its action is not always unambiguous. An attempt to explain the influence of the PEO treatment on the corrosion behavior of the alloy is presented.

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.

scholarly journals Influence of Different Electrolyte Additives and Structural Characteristics of Plasma Electrolytic Oxidation Coatings on AZ31 Magnesium Alloy

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 817
Author(s):  
Zhiquan Huang ◽  
Ruiqiang Wang ◽  
Xintong Liu ◽  
Dongdong Wang ◽  
Heng Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Ceramic Layer ◽  
Az31 Magnesium Alloy ◽  
Electrolyte Additives ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Coatings prepared by different electrolyte additives were investigated on AZ31 magnesium alloy by plasma electrolytic oxidation. In this study, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis were employed to assess the morphologies, chemical and phase compositions of the plasma electrolytic oxidation (PEO) coatings, respectively. Furthermore, electrochemical impedance spectroscopy was used to evaluate the corrosion behavior of the composite coating. The investigation of the effect of electrolyte additives in the base electrolyte showed that the PEO specimens exhibit different surface and cross-sectional morphologies, and phase compositions. The results showed that SiO32− was conducive to the growth of the ceramic layer, and the ceramic layer developing in the electrolyte which contained AlO2− showed a typical double-layer structure. The corrosion resistance of coating formed in a phosphate bath was higher than that of the coating formed in silicate bath and coating formed in an aluminate bath. Moreover, the corrosion resistance of the coating formed in the fluoride bath was the highest.

MODELING OF THE ELECTROLYZER ELECTRIC FIELD FOR PEO OF MAGNESIUM FOR THE STUDY OF SPECIAL CHAPTERS OF ELECTRICAL ENGINEERING

2019 ◽  
Author(s):  
Veta Mukaeva ◽  
E. Parfenov ◽  
R. Mukaev ◽  
M. Gorbatkov
Keyword(s):  
Magnesium Alloy ◽  
Electric Field ◽  
Plasma Electrolytic Oxidation ◽  
Electrical Engineering ◽  
Professional Competencies ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

The issue of modeling the distribution of the electric field in the electrolyzer during the plasma-electrolytic oxidation of a magnesium alloy for the motivation and formation of professional competencies for students in the study of electrical engineering disciplines is considered.

scholarly journals Investigation of Growth Mechanism of Plasma Electrolytic Oxidation Coating on Al-Ti Double-Layer Composite Plate

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 272 ◽  
Author(s):  
Quanzhi Chen ◽  
Weizhou Li ◽  
Kui Ling ◽  
Ruixia Yang
Keyword(s):  
Double Layer ◽  
Growth Mechanism ◽  
Plasma Electrolytic Oxidation ◽  
Composite Plate ◽  
Electrochemical Impedance ◽  
Electric Energy ◽  
Layer Composite ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Coating Growth

The aluminum–titanium (Al-Ti) double-layer composite plate is a promising composite material, but necessary surface protection was required before its application. In this paper, plasma electrolytic oxidation (PEO) was employed to fabricate a ceramic coating on the surface of a Al-Ti double-layer composite plate. To investigate the coating growth mechanism on the Al-Ti double-layer composite plate, a single-Al plate and a single-Ti plate were introduced for comparison experiments. Results showed that, the composite of Al and Ti accelerated the coating growth rate on the part-Ti portion of the composite plate, and that of the part-Al portion was decreased. Electrochemical impedance spectroscopy analysis indicated that the equivalent circuit of the Al-Ti coating was formed by connecting two different circuits in parallel. The reaction behavior revealed that the electric energy during the PEO would leak from the circuit with the weaker blocking effect, and confirmed that the electric energy distribution followed the law of low-resistance distribution. Finally, the mechanism was extended to the PEO treatment on general metal matrix composites to broaden the application theory of the technology.

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.

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