Energy-efficient PEO process of aluminium alloys

Matykina, E.; Arrabal, R.; Pardo, Á.; Mohedano, M.; Mingo, B.; Rodrı́guez, Ismael; González, Jorge Alfonso Murillo

doi:10.1016/j.matlet.2014.04.077

Cited by 72 publications

(30 citation statements)

References 22 publications

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“…The first anodizing step acquires a 10-30-fold reduction in power consumption to build up the necessary oxide. Matikyna and co-workers estimated that, for a~100 µm thick coating, PEO with a pre-anodized porous film might save 57% in energy consumption of the entire process [80][81][82]. The PEO of a pre-anodized film also reduces the PEO time with a controlled voltage mode, achieving 100 µm coating in 25 min, instead of 1-2 h in conventional soft sparking, if the anodizing time is not counted.…”

Section: Amassed Oxide and Energy Consumptionmentioning

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: Amassed Oxide and Energy Consumptionmentioning

confidence: 99%

Review of the Soft Sparking Issues in Plasma Electrolytic Oxidation

Tsai

Chou

2018

Metals

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“…These processes are used for surface finishing, including case hardening, nitriding and carbonitriding, [3,7,[17][18][19][20], surface oxidation [21][22][23][24][25], cleaning [26,27] and polishing [28][29][30] as well as stripping of defective coatings [6,31].…”

Section: Brief Characteristics Of Electrolytic Plasma Processesmentioning

confidence: 99%

“…The EPPo process which primary objective is to reduce surface roughness Ra has much higher rate in the beginning of the treatment, and this can be described by an exponential fall [68]. A typical EPP duration reaches tens of minutes, with the longest PEO treatments lasting up to several hours [25,73,102]. Therefore, for vector S, the time constant value ranges into hundreds of seconds (Table 1); this corresponds to the process evolution in the long time scale and can be adequately described with a sampling period in the range of minutes.…”

Section: Formalisation Possibilitiesmentioning

confidence: 99%

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

Парфенов

Yerokhin

Nev’yantseva

et al. 2015

Surface and Coatings Technology

151

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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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“…ACCEPTED MANUSCRIPT 3 The major problem in this justification is caused by application of high voltages (300-600 V) and high current densities (100-500 mA·cm -2 ) [2]. Operation at these conditions leads to a generation of plasma microdischarges and vapour gaseous envelope in the vicinity of the treated surface; this makes the system"s behaviour nonlinear and requires careful control of electric and thermal parameters required for the process [3].…”

Section: Accepted Manuscriptmentioning

confidence: 99%