Frequency response studies for the plasma electrolytic oxidation process

Парфенов, Е.В.; Yerokhin, Aleksey; Matthews, A.

doi:10.1016/j.surfcoat.2007.04.044

Cited by 65 publications

(48 citation statements)

References 7 publications

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“…The advantages of EPT are favorable character istics of gas discharges, such as low persistence and the possibility of varying parameters in broad ranges [86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101].…”

Section: Introductionmentioning

confidence: 99%

Electrolytic plasma processing for plating coatings and treating metals and alloys

Pogrebnyak

Kaverina

Кылышканов

2014

Prot Met Phys Chem Surf

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Abstract-A review of the methods of electrochemical treatment classified as plasma electrolysis is given. Special attention is paid to the physicochemical processes that proceed in electrolytes and the techniques of surface modification and application of protective coatings. The results of investigation of such coatings and surfaces upon electrolytic plasma processing illustrate the efficiency and effectiveness of the method. Being an efficient technique of the surface treatment, which involves both the surface cleaning and plating the coat ing, the plasma electrolytic method is being rapidly developed and adapted for commercial use at present.

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Section: Introductionmentioning

confidence: 99%

Electrolytic plasma processing for plating coatings and treating metals and alloys

Pogrebnyak

Kaverina

Кылышканов

2014

Prot Met Phys Chem Surf

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“…Figure 1 shows that cathodic MDs appear at a frequency higher than 2 kHz, a value in good agreement with theoretical results. Since cathodic discharges are associated with an increase in the cathodic current, it is interesting to note that Parfenov et al [7] and Yerokhin et al [34] have observed a significant increase in cathodic current starting in the kHz range when they swept the frequency in a range between 20 Hz and 20 kHz (see fig. 4 in [7] and fig.…”

mentioning

confidence: 99%

“…If this process has undeniable assets for surface treatments of light alloys (high growth rate, high ultimate coating thickness, ecofriendliness, wear and corrosion resistance, etc. ), the high energy consumption and the lack of understanding of the fundamental processes underlying the breakdown and the oxidation mechanisms still limit a larger scale development.Improving the energetic efficiency of PEO is a major stake and several strategies can then be followed: dual treatments[1], addition of nanoparticles [2,3], electrolyte composition [4,5] and electric regimes [5][6][7][8]. Here, we focus on the influence of the electric regime as it has a direct and strong influence on both the space and time properties of micro-discharges (MD), which affect the coating growth.…”

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confidence: 99%

High-Frequency-Induced Cathodic Breakdown during Plasma Electrolytic Oxidation

et al. 2017

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The present communication shows the possibility of observing micro-discharges under cathodic polarization during Plasma Electrolytic Oxidation (PEO) at high frequency. Cathodic micro-discharges can ignite beyond a threshold frequency found close to 2 kHz. The presence (resp. absence) of an Electrical Double Layer (EDL) was put forward to explain how the applied voltage can be screened, which therefore prevents (resp. promotes) the ignition of a discharge. Interestingly, in the conditions of the present study, the EDL requires between 175 and 260 µs to form. This situates the expected threshold frequency between 1.92 and 2.86 kHz, which is in good agreement with the value obtained experimentally.Plasma Electrolytic Oxidation (PEO) is at a pivotal moment of its development. If this process has undeniable assets for surface treatments of light alloys (high growth rate, high ultimate coating thickness, ecofriendliness, wear and corrosion resistance, etc.), the high energy consumption and the lack of understanding of the fundamental processes underlying the breakdown and the oxidation mechanisms still limit a larger scale development.Improving the energetic efficiency of PEO is a major stake and several strategies can then be followed: dual treatments[1], addition of nanoparticles [2,3], electrolyte composition [4,5] and electric regimes [5][6][7][8]. Here, we focus on the influence of the electric regime as it has a direct and strong influence on both the space and time properties of micro-discharges (MD), which affect the coating growth. Interestingly, the best properties and the highest growth rates of coatings are obtained while using bipolar current waveform [5,9] even though MDs are only observed during the anodic (i.e. positive) half-period [10][11][12] in these conditions.To explain this observation, one should keep in mind that the growth of PEO coatings relies on a balance between the constructive effect of MDs (oxidation and coating growth) and their destructive effect (large craters and porosities). Several studies conducted either by high speed video imaging [5,6,[11][12][13][14][15][16][17][18] or by direct electrical measurements [10,19] have investigated this balance. They made it possible to correlate space and time parameters of MDs (number, life-time, size) and the properties of as-grown coatings (thickness, porosity). In short, large and long-lived discharges promote the growth of high temperature phases but create large porosities (several tens of µm), high roughness at limited growth rates (strong destructive effect of MDs). On the other hand, too small and short-lived MDs will create more homogeneous coating but with lower amount of high-temperature phases and also at limited growth rates (weak constructive effect).Nevertheless, all these studies support the same conclusion: adjusting the cathodic half period probably opens up the possibility to tune the behaviour of anodic MDs. Then, combining high-growth rates, low levels of large-scale porosity (bigger than 10 µm) and a significant proportio...

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“…Yerokhin et al and R.O. Hussein et al related to the influence of electrical parameters on coating characteristics in pulsed PEO coating process for Al and Al alloys [1][2][3]. However, the materials in their investigations were limited to 1000 or 6000 series Al alloy, and only a few studies have dealt with Al-Mg alloy.…”

Section: Introductionmentioning

confidence: 99%

Influence of Applied Frequency on Microstructural and Electrochemical Characteristics of Ceramic Coating Produced on Al-Mg Alloy by Pulsed Plasma Electrolytic Oxidation

Lee

Kim

2016

Acta Phys. Pol. A

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Plasma electrolytic oxidation (PEO) coating is gaining attention as a promising surface treatment technique for lightweight metals and alloys such as Al, Mg and Ti. The coating involves complex interactions among various process parameters including substrate composition, current modes and electrolyte composition. In this study, ceramic coating was produced in silicate based alkaline solution on Al-Mg alloy by pulsed PEO with different applied frequencies (100, 500, 1000, 2000 Hz). The resultant coating was characterized using FE-SEM, EDS and HR-XRD. The electrochemical characteristics of the PEO coating were also investigated in seawater solution. It was found that changing frequency in the PEO process had a prominent effect on both surface and crosssectional morphology of the coating. The electrochemical studies indicated that the pulsed PEO have improved the corrosion resistance of the Al-Mg substrate. In particular, the applied frequency of 100 Hz has produced one order of magnitude lower corrosion current density than that of the Al-Mg substrate.

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Frequency response studies for the plasma electrolytic oxidation process

Cited by 65 publications

References 7 publications

Electrolytic plasma processing for plating coatings and treating metals and alloys

Electrolytic plasma processing for plating coatings and treating metals and alloys

High-Frequency-Induced Cathodic Breakdown during Plasma Electrolytic Oxidation

Influence of Applied Frequency on Microstructural and Electrochemical Characteristics of Ceramic Coating Produced on Al-Mg Alloy by Pulsed Plasma Electrolytic Oxidation

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