Plasma electrolytic oxidation of AM60 magnesium alloy: Monitoring by acoustic emission technique. Electrochemical properties of coatings

Boinet, Mickaël; Verdier, Stéphane; Maximovitch, S.; Dalard, F.

doi:10.1016/j.surfcoat.2004.10.145

Cited by 62 publications

(38 citation statements)

References 21 publications

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“…On these issues, researchers are fully aware of the critical need for a tool to quantify the plasma state in an aqueous electrolyte. Optical, electrical, and acoustic signals have been studied for that purpose [54,[61][62][63][64][65]. Current OES technique has achieved more success than the other two, and is on its way to being an in situ diagnostic tool [66][67][68][69].…”

Section: Plasma State In Electron Temperaturementioning

confidence: 99%

Review of the Soft Sparking Issues in Plasma Electrolytic Oxidation

Tsai

Chou

2018

Metals

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Abstract:A dense inner layer is highly valued among the surface coatings created through plasma electrolytic oxidation (PEO) treatment, because the PEO coating has been troubled by inherent porosity since its conception. To produce the favored structure, a proven technique is to prompt a soft sparking transition, which involves a sudden decrease in light and acoustic emissions, and a drop in anodic voltage under controlled current mode. Typically these phenomena occur in an electrolyte of sodium silicate and potassium hydroxide, when an Al-based sample is oxidized with an AC or DC (alternating or direct current) pulse current preset with the cathodic current exceeding the anodic counterpart. The dense inner layer feature is pronounced if a sufficient amount of oxide has been amassed on the surface before the transition begins. Tremendous efforts have been devoted to understand soft sparking at the metal-oxide-electrolyte interface. Studies on aluminum alloys reveal that the dense inner layer requires plasma softening to avoid discharge damages while maintaining a sufficient growth rate, a porous top layer to retain heat for sintering the amassed oxide, and proper timing to initiate the transition and end the surface processing after transition. Despite our understanding, efforts to replicate this structural feature in Mg-and Ti-based alloys have not been very successful. The soft sparking phenomena can be reproduced, but the acquired structures are inferior to those on aluminum alloys. An analogous quality of the dense inner layer is only achieved on Mg-and Ti-based alloys with aluminate anion in the electrolytic solution and a suitable cathodic current. These facts point out that the current soft sparking knowledge on Mg-and Ti-based alloys is insufficient. The superior inner layer on the two alloys still relies on rectification and densification of aluminum oxide.

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Section: Plasma State In Electron Temperaturementioning

confidence: 99%

Review of the Soft Sparking Issues in Plasma Electrolytic Oxidation

Tsai

Chou

2018

Metals

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“…[37,89], type of boiling [90], optical emission intensity [4,91,92] and spectral content [38,93,94] associated with the VGE. Acoustic techniques could be also informative [95,96].…”

Section: Electrical Characteristics Of the Subsystemsmentioning

confidence: 99%

“…This is a new, important and challenging problem, solutions for which just started to appear [95,97,109,110].…”

Section: Formalisation Possibilitiesmentioning

confidence: 99%

“…As seen from the phenomenological model structure (Fig.10, block 3.3.2), several approaches to the process diagnostics are available, e.g. based on the analysis of electrical [104,114,115], optical [38,91,93,94,116] and acoustic [95] characteristics, video imaging [36,37], and their various combinations [4,96,117].…”

Section: Regression Modelling and Design Of Experiments 22mentioning

confidence: 99%

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Towards smart electrolytic plasma technologies: An overview of methodological approaches to process modelling

Парфенов

Yerokhin

Nev’yantseva

et al. 2015

Surface and Coatings Technology

160

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Article:Parfenov, E.V., Yerokhin, A., Nevyantseva, R. ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Abstract This paper reviews the present understanding of electrolytic plasma processes (EPPs) and approaches to their modelling. Based on the EPP type, characteristics and classification, it presents a generalised phenomenological model as the most appropriate one from the process diagnostics and control point of view. The model describes the system 'power supply -electrolyser -electrode surface' as a system with lumped parameters characterising integral properties of the surface layer and integral parameters of the EPP. The complexity of EPPs does not allow the drawing of a set of differential equations describing the treatment, although a model can be formalised for a particular process as a black box regression. Evaluation of dynamic properties reveals the multiscale nature of electrolytic plasma processes, which can be described by three time constants separated by 2-3 orders of magnitude (minutes, seconds and milliseconds), corresponding to different groups of characteristics in the model. Further developments based on the phenomenological approach and providing deeper insights into EPPs are proposed using frequency response methodology and electromagnetic field modelling. Examples demonstrating the efficiency of the proposed approach are supplied for EPP modelling with static and dynamic neural networks, frequency response evaluations and electromagnetic field calculations.

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“…A good number of surface modification procedures have been developed and contemplated with a reasonable degree of success for different applications [7][8][9]. The plasma electrolytic oxidation (PEO) treatment has been found to be quite effective in improving the tribological and corrosion properties of magnesium alloys [10][11][12]. Even though many researchers have assessed the general corrosion behaviour of PEO coated magnesium alloys, there seems to be no published information on the stress corrosion cracking behaviour of magnesium alloys with PEO coating available.…”

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confidence: 99%