Plasma electrolytic oxidation (PEO) coatings on Mg-alloys for improved wear and corrosion resistance

Titanium, magnesium and zirconium alloys are widely used in industrial applications, which require high wear and corrosion resistance. However current methods of improving these properties often do not satisfy the requirements of service and functional properties. An alternative approach is the application of oxide-ceramic coatings using high temperature process. The coatings are applied by spark discharge plasma in the metal-electrolyte system at high voltages - PEO (plasma electrolytic oxidation) as an oxide synthesis method. This method has shown good results for aluminium alloys and with good prospects to be used for titanium, magnesium and zirconium alloys. Development of PEO technology to improve the wear and corrosion resistance of titanium, magnesium and zirconium alloys is discussed in this paper. It describes the methods for obtaining the required layer-thickness for a specified hardness, porosity, wear and corrosion resistance, sets up the optimal process parameters (voltage/current) by taking the relation of anodic to cathodic currents into account, and establishing the electrolyte content of different dopants.

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Investigation of wear and corrosion resistance of nanocomposite coating formed on AZ31B Mg alloy by plasma electrolytic oxidation

Transactions of the IMF ◽

10.1080/00202967.2017.1355978 ◽

2017 ◽

Vol 95 (6) ◽

pp. 308-315 ◽

Cited By ~ 2

Author(s):

H. Nasiri Vatan ◽

M. Adabi

Keyword(s):

Corrosion Resistance ◽

Plasma Electrolytic Oxidation ◽

Nanocomposite Coating ◽

Mg Alloy ◽

Wear And Corrosion ◽

Electrolytic Oxidation ◽

Wear And Corrosion Resistance ◽

Plasma Electrolytic

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The effect of process current parameters on the properties of oxide layers under plasma electrolytic oxidation of AMg6 alloy

Journal of Physics Conference Series ◽

10.1088/1742-6596/2144/1/012018 ◽

2021 ◽

Vol 2144 (1) ◽

pp. 012018

Author(s):

A V Polunin ◽

A G Denisova ◽

A O Cheretaeva ◽

M R Shafeev ◽

E D Borgardt ◽

...

Keyword(s):

Wear Resistance ◽

Corrosion Resistance ◽

Plasma Electrolytic Oxidation ◽

Oxide Layers ◽

Positive Pulse ◽

Pulse Ratio ◽

Wear And Corrosion ◽

Electrolytic Oxidation ◽

Wear And Corrosion Resistance ◽

Plasma Electrolytic

Abstract The effect of current density and current ratio in the cathodic and anodic half-cycles during prolonged (180 minutes) plasma electrolytic oxidation (PEO) of AMg6 wrought alloy on the oxide layer wear and corrosion resistance were studied. It was established that the best wear resistance is achieved in the oxide layers obtained in the “soft sparking” mode (negative-to-positive pulse ratios of 1.15–1.30) at current densities of 9–15 A dm−2, and the best set of wear resistance and corrosion resistance – in the oxide layers obtained in “symmetrical” mode (negative-to-positive pulse ratio of 1.00).

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Plasma Electrolytic Oxidation (PEO) Process—Processing, Properties, and Applications

Nanomaterials ◽

10.3390/nano11061375 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1375

Author(s):

Soumya Sikdar ◽

Pramod V. Menezes ◽

Raven Maccione ◽

Timo Jacob ◽

Pradeep L. Menezes

Keyword(s):

Plasma Electrolytic Oxidation ◽

Nanocomposite Coatings ◽

Mechanical And Tribological Properties ◽

Electrolytic Oxidation ◽

Recent Developments ◽

Coating Formation ◽

Wear And Corrosion Resistance ◽

Plasma Electrolytic ◽

Peo Coatings ◽

Future Work

Plasma electrolytic oxidation (PEO) is a novel surface treatment process to produce thick, dense metal oxide coatings, especially on light metals, primarily to improve their wear and corrosion resistance. The coating manufactured from the PEO process is relatively superior to normal anodic oxidation. It is widely employed in the fields of mechanical, petrochemical, and biomedical industries, to name a few. Several investigations have been carried out to study the coating performance developed through the PEO process in the past. This review attempts to summarize and explain some of the fundamental aspects of the PEO process, mechanism of coating formation, the processing conditions that impact the process, the main characteristics of the process, the microstructures evolved in the coating, the mechanical and tribological properties of the coating, and the influence of environmental conditions on the coating process. Recently, the PEO process has also been employed to produce nanocomposite coatings by incorporating nanoparticles in the electrolyte. This review also narrates some of the recent developments in the field of nanocomposite coatings with examples and their applications. Additionally, some of the applications of the PEO coatings have been demonstrated. Moreover, the significance of the PEO process, its current trends, and its scope of future work are highlighted.

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Effects of a Carbon Nanotube Additive on the Corrosion-Resistance and Heat-Dissipation Properties of Plasma Electrolytic Oxidation on AZ31 Magnesium Alloy

Materials ◽

10.3390/ma11122438 ◽

2018 ◽

Vol 11 (12) ◽

pp. 2438 ◽

Cited By ~ 4

Author(s):

Myungwon Hwang ◽

Wonsub Chung

Keyword(s):

Corrosion Resistance ◽

Carbon Nanotube ◽

Plasma Electrolytic Oxidation ◽

Heat Dissipation ◽

X Ray ◽

Steady State Method ◽

Electrolytic Oxidation ◽

Plasma Electrolytic ◽

Dissipation Property ◽

Peo Coatings

Plasma electrolytic oxidation (PEO) coating was obtained on AZ31 Mg alloy using a direct current in a sodium silicate-based electrolyte with and without a carbon nanotube (CNT) additive. The surface morphology and phase composition of the PEO coatings were investigated through field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The corrosion-resistance properties of the PEO coatings were evaluated using potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution. Furthermore, the heat-dissipation property was evaluated by a heat-flux measurement setup using a modified steady-state method and Fourier transform infrared spectroscopy (FT-IR). The results demonstrate that, by increasing the concentration of CNT additive in the electrolyte, the micropores and cracks of the PEO coatings are greatly decreased. In addition, the anticorrosion performance of the PEO coatings that incorporated CNT for the protection of the Mg substrate was improved. Finally, the coating’s heat-dissipation property was improved by the incorporation of CNT with high thermal conductivity and high thermal emissivity.

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Influence of Complex SiF62− Ions on the PEO Coatings Formed on Mg–Al6–Zn1 Alloy for Enhanced Wear and Corrosion Protection

Coatings ◽

10.3390/coatings10020094 ◽

2020 ◽

Vol 10 (2) ◽

pp. 94 ◽

Cited By ~ 2

Author(s):

Zeeshan Ur Rehman ◽

Bon Heun Koo ◽

Dongjin Choi

Keyword(s):

Plasma Electrolytic Oxidation ◽

Optimum Concentration ◽

Wear Properties ◽

Sem Image ◽

Wear And Corrosion ◽

Electrolytic Oxidation ◽

Plasma Electrolytic ◽

Peo Coatings ◽

Sem Image Analysis ◽

Scanning Electron

The present study was carried out to explore the effect of SiF62− incorporation and concentration on the plasma electrolytic oxidation (PEO) coatings formed on AZ61 Mg alloy. The coatings were prepared using electrolyte solution with various concentration of Na2SiF6 (0.0–0.7 g/L). Highly compact coatings with minimum porosity were obtained for an optimum concentration of Na2SiF6 ~0.3 g/L added into the electrolyte. The highest corrosion resistance, ~2.04 × 105 Ω·cm2, was obtained for 0.3 g/L of Na2SiF6, in addition to its superior anti-wear properties. However, it was found from the scanning electron microscope (SEM) image analysis that increasing concentration above 0.3 g/L, could cause severe breakdown in the inner layers, and thus the said coatings could not withstand effectively against wear and corrosion.

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Wear and Corrosion Resistance of Plasma Electrolytic Oxidation Coatings on 6061 Al Alloy in Electrolytes with Aluminate and Phosphate

Materials ◽

10.3390/ma14144037 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4037

Author(s):

Zhenjun Peng ◽

Hui Xu ◽

Siqin Liu ◽

Yuming Qi ◽

Jun Liang

Keyword(s):

Corrosion Resistance ◽

Plasma Electrolytic Oxidation ◽

Salt Spray ◽

P Element ◽

Alumina Coating ◽

Al Alloy ◽

Wear Properties ◽

Electrolytic Oxidation ◽

Plasma Electrolytic ◽

Peo Coatings

Phosphate and aluminate electrolytes were used to prepare plasma electrolytic oxidation (PEO) coatings on 6061 aluminum alloy. The surface and cross-section microstructure, element distribution, and phase composition of the PEO coatings were characterized by SEM, EDS, XPS, and XRD. The friction and wear properties were evaluated by pin-on-disk sliding tests under dry conditions. The corrosion resistance of PEO coatings was investigated by electrochemical corrosion and salt spray tests in acidic environments. It was found that the PEO coatings prepared from both phosphate and aluminate electrolytes were mainly composed of α-Al2O3 and γ-Al2O3. The results demonstrate that a bi-layer coating is formed in the phosphate electrolyte, and a single-layered dense alumina coating with a hardness of 1300 HV is realizable in the aluminate electrolyte. The aluminate PEO coating had a lower wear rate than the phosphate PEO coating. However, the phosphate PEO coating showed a better corrosion resistance in acidic environment, which is mainly attributed to the presence of an amorphous P element at the substrate/coating interface.

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Special Issue: Plasma Electrolytic Oxidation (PEO) Coatings

Coatings ◽

10.3390/coatings11010111 ◽

2021 ◽

Vol 11 (1) ◽

pp. 111

Author(s):

Marta Mohedano ◽

Beatriz Mingo

Keyword(s):

Corrosion Resistance ◽

Plasma Electrolytic Oxidation ◽

Special Issue ◽

Wear Properties ◽

Technological Society ◽

Good Corrosion Resistance ◽

Functionalized Surfaces ◽

Electrolytic Oxidation ◽

Plasma Electrolytic ◽

Peo Coatings

The demand of modern technological society for light structural materials (Al, Ti, Mg) emphasizes a combination of good corrosion resistance with wear properties and functionalized surfaces [...]

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