The Electrolyte Concentration Influence on the Features of Formation Process and Morphology of the PEO-Coatings on Aluminum Alloy

2018 ◽  
Vol 386 ◽  
pp. 309-314 ◽  
Author(s):  
Vladimir S. Egorkin ◽  
Igor E. Vyaliy ◽  
Nikolay V. Izotov ◽  
Sergey L. Sinebryukhov ◽  
Sergey V. Gnedenkov

Plasma electrolytic oxidation (PEO) of aluminum alloy 5754 was carried out in a multicomponent electrolyte variating the concentration of sodium silicate. The research has allowed to establish the characteristic features of the plasma electrolytic oxidation process, and also morphological structure of the formed oxide layers. It is established that the applied electrolytic systems can significantly increase the thickness of the formed layers (up to 152 μm), and control their porosity, bringing it up to 30 %.

2021 ◽  
Vol 2144 (1) ◽  
pp. 012020
Author(s):  
I A Rastegaev ◽  
A V Polunin

Abstract The paper highlights the characteristic features of acoustic emission (AE) in the process of plasma electrolytic oxidation (PEO) of aluminum alloy, and also reveals the correlation of 4 main stages of PEO process with AE signals. The fundamental possibility to establish and detail the features of oxidation stages and to compare different PEO modes by AE signals was demonstrated. The results obtained substantiate the high potential of AE method as an instrument of in situ research, production monitoring and control, and evaluation of quality of PEO process on aluminum alloys.


2020 ◽  
Vol 67 (1) ◽  
pp. 48-58
Author(s):  
Wanying Liu ◽  
Junjie Yang ◽  
Yuhong Qiu ◽  
Ying Liu ◽  
Kuanhai Deng

Purpose The preferable concentration of titanium carbide was optimized and added as an additive to the micro-arc oxidation electrolyte to produce a high corrosion-resistant coating on D16T aluminum alloy. Design/methodology/approach Ceramic coatings were deposited on D16T aluminum alloy by plasma electrolytic oxidation in alkaline silicate electrolytes with micron titanium carbide particle suspending at different concentrations. Influences of additive concentration on morphology, elemental and phase composition and corrosion resistance of doped PEO coatings were evaluated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and electrochemical methods, respectively. Findings Results revealed that suspending titanium carbide additives incorporated into ceramic coatings through discharging channels and chemically transformed into amorphous stage. The content of titanium in the doped coatings increased with the increasing concentration of suspending micron additive. Compared with the coating without particle addition, the corrosion resistance of the coating produced in 8 g/L titanium carbide suspension increased more than 20 times. The result indicated that the incorporation of titanium into the PEO coatings formed on the D16T aluminum alloy could effectively improve the corrosion resistance. Originality/value The mechanism of corporation of TiC and the mechanism of improving the corrosion resistance of the coating were proposed.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1375
Author(s):  
Soumya Sikdar ◽  
Pramod V. Menezes ◽  
Raven Maccione ◽  
Timo Jacob ◽  
Pradeep L. Menezes

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.


Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Dmitry V. Dzhurinskiy ◽  
Stanislav S. Dautov ◽  
Petr G. Shornikov ◽  
Iskander Sh. Akhatov

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.


Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 401
Author(s):  
Ruzil Farrakhov ◽  
Olga Melnichuk ◽  
Evgeny Parfenov ◽  
Veta Mukaeva ◽  
Arseniy Raab ◽  
...  

The paper compares the coatings produced by plasma electrolytic oxidation (PEO) on commercially pure titanium and a novel superelastic alloy Ti-18Zr-15Nb (at. %) for implant applications. The PEO coatings were produced on both alloys in the identical pulsed bipolar regime. The properties of the coatings were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). The PEO process kinetics was modeled based on the Avrami theorem and Cottrell equation using a relaxation method. The resultant coatings contain TiO2, for both alloys, and NbO2, Nb2O5, ZrO2 for Ti-18Zr-15Nb alloy. The coating on the Ti-18Zr-15Nb alloy has a higher thickness, porosity, and roughness compared to that on cp-Ti. The values of the kinetic coefficients of the PEO process—higher diffusion coefficient and lower time constant for the processing of Ti-18Zr-15Nb—explain this effect. According to the electrochemical studies, PEO coatings on Ti-18Zr-15Nb alloy provide better corrosion protection. Higher corrosion resistance, porosity, and roughness contribute to better biocompatibility of the PEO coating on Ti-18Zr-15Nb alloy compared to cp-Ti.


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