scholarly journals Influences of Growth Species and Inclusions on the Current–Voltage Behavior of Plasma Electrolytic Oxidation: A Review

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 270
Author(s):  
Dah-Shyang Tsai ◽  
Chen-Chia Chou
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Time Frame ◽  
Transportation Industry ◽  
Cathodic Current ◽  
Surface Protection ◽  
Precise Control ◽  
Current Voltage ◽  
Electrolytic Oxidation ◽  
Long Time ◽  
Plasma Electrolytic

Plasma electrolytic oxidation (PEO) has attracted increasing attention since the transportation industry adopts more lightweight metal components and requires an improved version of anodizing for surface protection. In response to the demand, researchers enrich the technical connotation of PEO through diversifying the growth paths and adopting new precursors. Foreign electrolyte additives, involving ceramic and polymeric particles, organic dye emulsions, are incorporated to accomplish various goals. On the other hand, significant progress has been made on comprehension of softening sparks; denoting the adverse trend of growing discharge intensity can be re-routed by involving cathodic current. I–V response shows the cathodic pulse current not only cools down the ensuing anodic pulse, but also twists the coating conductivity, and the residuals of twists accumulate over a long time frame, plausibly through oxide protonation. Thus, the cathodic current provides a tool to control the discharge intensity via integration of the coating conductivity deviations. So far, these cathodic current studies have been performed in the electrolytes of KOH and Na2SiO3. When exotic additives are included, for example Cr2O3, the cathodic current effect is also shifted, as manifested in remarkable changes in its current–voltage (I–V) behavior. We anticipate the future study on cathodic current influences of inclusion shall lead to a precise control of micro arc.

Growth Characteristics of the Oxide Layer on Aluminium in the Process of Plasma Electrolytic Oxidation

2014 ◽  
Vol 59 (1) ◽  
pp. 407-411 ◽  
Author(s):  
W. Gębarowski ◽  
S. Pietrzyk
Keyword(s):  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Electrochemical Impedance ◽  
Sudden Change ◽  
Charge Transfer Resistance ◽  
Cathodic Current Density ◽  
Cathodic Current ◽  
Transfer Resistance ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Abstract During the formation of the oxide layer by plasma electrolytic oxidation (PEO), the electrochemical processes are accompanied by the plasma micro-discharges, occurring uniformly over the coated electrode. Application of an alternating current with strictly controlled electrical parameters can affect the character of the discharges, and consequently the properties of the obtained layers. When the cathodic current density exceeds anodic, at some point, a sudden change in the appearance of micro-discharges and a decrease in the intensity of the acoustic emission can be observed - in literature this effect is called “soft sparking”. In the present work, the evolution of the electrical properties of the layers at various stages of their formation has been characterized, using electrochemical impedance spectroscopy. The study showed a significant decrease in charge transfer resistance and increase in capacitance of the oxide layer after reaching the ”soft sparking”. This indicates a significant change in the structure of the oxide layer, in the barrier and main part, which is additionally confirmed by measuring the breakdown voltage.

Influence of the Cathodic Pulse on the Formation and Morphology of Oxide Coatings on Aluminium Produced by Plasma Electrolytic Oxidation / Wpływ Impulsu Katodowego Na Tworzenie I Morfologie Warstw Tlenkowych Na Aluminium Otrzymywanych Na Drodze Plazmowego Utleniania Elektrolitycznego

2013 ◽  
Vol 58 (1) ◽  
pp. 241-245 ◽  
Author(s):  
W. Gebarowski ◽  
S. Pietrzyk
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Density Ratio ◽  
Alternate Current ◽  
Xrd Analysis ◽  
Ceramic Coatings ◽  
Cathodic Current Density ◽  
Cathodic Current ◽  
Cathodic Pulse ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

Plasma electrolytic oxidation (PEO) is an effective method to obtain hard ceramic coatings on Al, Mg and Ti alloys. Micro-discharges occurring on the electrode surface during process promote the creation of crystalline oxides phases which improve mechanical properties of the coating. By using alternate current (AC) at some current conditions the process can be conducted in ‘soft’ spark regime. This allows producing thicker layers, increasing growth rate and uniformity of layer, decreasing amount of pores and defects. These facts proof the importance of cathodic pulse in the PEO mechanism; however its role is not well defined. In this work, influence of anodic to cathodic current density ratio on kinetics of coating growth, its morphology and composition were investigated. The PEO process of pure was conducted in potassium hydroxide with sodium metasilicate addition. The different anodic to cathodic average currents densities ratios of pulses were applied. The phase composition of coatings was determined by XRD analysis. Morphology of obtained oxide layers was investigated by SEM observations.

scholarly journals Effect of Hydrogen on the Wear Resistance of Steels upon Contact with Plasma Electrolytic Oxidation Layers Synthesized on Aluminum Alloys

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 280 ◽  
Author(s):  
Volodymyr Hutsaylyuk ◽  
Mykhailo Student ◽  
Volodymyr Dovhunyk ◽  
Volodymyr Posuvailo ◽  
Oleksandra Student ◽  
...  
Keyword(s):  
Plasma Electrolytic Oxidation ◽  
Mineral Oil ◽  
Carbon Steels ◽  
Spinel Type ◽  
Friction Zone ◽  
Surface Protection ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic ◽  
Friction Surfaces ◽  
Oxidation Layers

The different nature of the effect of hydrogen on the tribological behavior of two carbon steels (st. 45 and st. U8) upon their contact with super solid plasma electrolytic oxidation (PEO) layers synthesized on two light alloys (AMg-6 and D16T alloys as the analogists of the A 95556 UNS USA and AA2024 ANSI USA alloys correspondently) was investigated in the medium of mineral oil of the I-20 type. To compare the effect of hydrogenation on the tribological properties of the analyzed contact pairs, similar tests were also performed on the same mineral oil with clear water or an aqueous solution of glycerine added to its content. A spinel-type film (hercynite) was formed upon friction of two contacting surfaces—the iron-carbon steels and PEO layers synthesized on the AMg-6 alloy. This film was a reliable protection against wear of the surface subjected to the effect of hydrogen. When steels came into contact with the PEO layers synthesized on the D16T alloy, surface protection against wear was ensured by another mechanism. The phenomenon of selective metal transfer in the friction zone (from one to another friction surfaces) was revealed.

ffect of Na2WO4 in electrolyte on mechanical properties of oxide layer on Al alloy via plasma electrolytic oxidation

2015 ◽  
Vol 53 (8) ◽  
pp. 535-540 ◽  
Author(s):  
Young Gun Ko ◽  
Dong Hyuk Shin ◽  
Hae Woong Yang ◽  
Yeon Sung Kim ◽  
Joo Hyun Park ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Al Alloy ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic
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