Plasma electrolytic oxidation of pre-anodized aluminium

Matykina, E.; Arrabal, R.; Mohamed, A.E.; Skeldon, P.; Thompson, G.E.

doi:10.1016/j.corsci.2009.08.004

Cited by 90 publications

(43 citation statements)

References 30 publications

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“…-Al 2 O 3 ) desirable for tribological applications [3]. Coatings with a denser intermediate layer are formed under ac and bipolar conditions due to the establishment of a particular microarc regime that is commonly referred to as "soft sparking" [15,16]. The transition to this regime commences after a sufficient thickness of the coating has been achieved (15-20 m) and is characterized by contraction of the positive column of the microarc discharge, low acoustic emission and increased emissions from bound-free electron transitions in the optical spectrum of the microdischarges [11,17,18].…”

Section: Introductionmentioning

confidence: 99%

Energy-efficient PEO process of aluminium alloys

et al. 2014

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of the original manuscript:Matykina, E.; Arrabal, R.; Pardo, A.; Mohedano, M.; Mingo, B.; Rodriguez, I.; Gonzalez, J.: Energy-efficient PEO process of aluminium alloys AbstractThe influence of pre-anodizing in sulphuric and phosphoric acids on energy efficiency of voltage-controlled PEO process of three commercial wrought and cast aluminium alloys (AA1050, AA6082 and A356) has been investigated. The precursor anodic porous films enable up to 57% energy savings during PEO and produce ~35-40% increase of the coating microhardness compared with direct PEO. Total specific energy consumption values of 2.5-2.7 kW h m -2 µm -1 and 3.1-3.8 kW h m -2 µm -1 were achieved using phosphoric and sulphuric acid-formed precursors, respectively.

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Section: Introductionmentioning

confidence: 99%

Energy-efficient PEO process of aluminium alloys

et al. 2014

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“…The lower concentration of oxygen (Fig. 8c) and higher concentration of aluminium ( In PEO of aluminium in alkaline silicate electrolyte, less porous and relatively uniform oxide layer can be formed after transition to "soft" sparking [8,9,12,[15][16][17][18]. The present study reveals that healing open discharge pores occurs more readily during single pulse anodizing in alkaline silicate electrolyte, while such healing is not observed in ammonium pentaborate electrolyte.…”

Section: Methodsmentioning

confidence: 62%

“…It has been recently reported that relatively thick intermediate layer with low porosity is formed between an inner barrier layer and an outer loose layer containing large cavities and pores under selected PEO conditions [8,9,12,[15][16][17][18]. The formation of the intermediate layer is correlated with so called "soft" sparking, which is characterized by a change in the optical emission spectra, reduction in the size of microdischarges and reduction in acoustic noise [16,19].…”

Section: Introductionmentioning

confidence: 99%

“…The coatings can range from tens to hundreds of micrometres in thickness, and their improved thermo-mechanical properties, corrosion resistance and wear resistance [1,[5][6][7][8][9] are partly associated with the formation of high-temperature oxide phases, such as -Al 2 O 3 , during PEO processing. The process involves a large number of short-lived microdischarges, caused by dielectric breakdown of oxide coatings at high voltages.…”

Section: Introductionmentioning

confidence: 99%

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Dielectric breakdown and healing of anodic oxide films on aluminium under single pulse anodizing

et al. 2011

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Single pulse anodizing of aluminium micro-electrode has been employed to study the behaviour of dielectric breakdown and subsequent oxide formation on aluminium in alkaline silicate and pentaborate electrolytes. Current transients during applying pulse voltage have been measured, and surface has been observed by scanning electron microscopy. Two types of current transients are observed, depending on the electrolyte and applied voltage. There is a good correlation between the current transient behaviour and the shape of discharge channels. In alkaline silicate electrolyte, circular open pores are healed by increasing the pulse width, but such healing is not obvious in pentaborate electrolyte.

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“…Formation of PEO coatings is closely related with generation of micro-arcs on the surface of metallic substrates in aqueous alkaline electrolytes [1][2][3][4][5][6][7][8][9][10]. Al alloys are readily dissolved in alkaline solutions but anodic oxide film can grow if appropriate anions are provided [3,12,13].…”

Section: Introductionmentioning

confidence: 99%

Lateral Growth of PEO Films on Al1050 Alloy in an Alkaline Electrolyte

Moon¹,

Kim²

2017

Journal of the Korean institute of surface engineering

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This article reports for the first time on the lateral growth of PEO (plasma electrolytic oxidation) films on Al1050 alloy by the application of anodic pulse current in an alkaline electrolyte. Generation of microarcs was observed at the edges initially and then moved towards the central region with PEO treatment time. Disc type PEO film islands with about 20 µm diameter were formed first and they grew laterally by the formation of new disc type PEO films at the edge of pre-formed PEO islands. The PEO film islands were found to be interconnected completely and form a continuous PEO film when generation of small size microarcs are terminated at the central part of the specimen, resulting in very smooth surface with low surface roughness less than 1 µm of R a . Further PEO treatment after the complete interconnection of PEO films islands showed local thickening of PEO films by vertical growth. It is concluded that very smooth PEO film surface can be obtained by lateral growth mechanism rather than vertical growth of them.

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Plasma electrolytic oxidation of pre-anodized aluminium

Cited by 90 publications

References 30 publications

Energy-efficient PEO process of aluminium alloys

Energy-efficient PEO process of aluminium alloys

Dielectric breakdown and healing of anodic oxide films on aluminium under single pulse anodizing

Lateral Growth of PEO Films on Al1050 Alloy in an Alkaline Electrolyte

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