Characterization and wear- and corrosion-resistance of microarc oxidation ceramic coatings on aluminum alloy

Wei, Tongbo; Yan, Fengyuan; Tian, Jun

doi:10.1016/j.jallcom.2004.05.084

Cited by 203 publications

(88 citation statements)

References 14 publications

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“…Micro-cracking of the MAO coating is mainly associated with the thermal stress initiated during rapid solidification of the alumina melted in the discharge tunnel. 21 The micro-pores were mainly ranged from about 1 μm to 3 μm in diameter. The thickness of the MAO coating was about 12 μm.…”

Section: Resultsmentioning

confidence: 99%

“…It is suggested that the outer sections of the MAO coating were primarily dominated by g-Al 2 O 3 owing to the higher cooling rate, while the inner section was mainly comprised of a-Al 2 O 3 as a result of more heat input gained during the MAO process. 15,21 In Figure 3 contact angles measured on the as-received alloy (Al-6061), micro-arc oxidized alloy (MAO), sealed as-received alloy (Al-6061+S) and sealed MAO applied alloy (MAO+S) are presented. The as-received 6061 aluminum alloy and MAO samples exhibited low contact angles, as indicated by the high hydrophilicity and patelliform shape.…”

Section: Resultsmentioning

confidence: 99%

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Formation of a corrosion-resistant alumina coating on a 6061 aluminum alloy using a combination of micro-arc oxidation and sealing treatments

Paksoy¹,

Muhaffel²,

Koca³

et al. 2017

Mater. Tehnol.

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Micro-arc oxidation (MAO) is an attractive process for the fabrication of protective coatings on aluminum alloys used in many industrial applications, such as automotive, structural and aerospace. However, improvements in the corrosion resistance of aluminum alloys upon covering their surfaces with MAO coating may not be sufficient for extending the service life of the components utilized in harsh environments. In the present study, the MAO coating formed on a 6061 aluminum alloy was sealed using a stearic acid treatment. In the scope of the present study, the surface and cross-sectional microstructures and the phases of the MAO coatings were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques, respectively. The wettability and surface roughness of the samples were measured by goniometer and profilometer, respectively. The corrosion resistance was assessed by long-term immersion in 3.5 % of mass fractions NaCl solution. Finally, it is concluded that sealing of the MAO coating by stearic acid treatment significantly improved the corrosion resistance of the 6061 quality aluminum alloy as compared to the untreated state and the unsealed MAO state. Keywords: aluminum alloy, micro-arc oxidation, ceramic coating, sealing, corrosion.Oksidacija v mikroobloku (MAO) je zanimiv postopek za izdelavo za{~itnih nanosov na aluminijevih zlitinah, ki se jih uporablja v {tevilnih industrijah, kot je avtomobilska, gradbeni{tvo in letalstvo. Vendar pa izbolj{anje korozijske odpornosti aluminijevih zlitin po prekritju z MAO nanosom ni dovolj veliko za podalj{anje zdr`ljivosti komponent, ki se jih uporablja v kislih okoljih. V {tudiji je bila plast MAO, ki je nastala na zlitini aluminija 6061, zatesnjena z obdelavo s stearinsko kislino. V okviru te {tudije, so bile analizirane povr{ine in mikrostrukture preseka in faze v MAO nanosu, s pomo~jo elektronske vrsti~ne mikroskopije (SEM) in z rentgensko difrakcijo (XRD). Omo~ljivost in hrapavost povr{ine vzorcev sta bili izmerjeni z goniometrom in s profilometrom. Korozijska odpornost je bila dolo~ena z dolgotrajnim namakanjem v 3,5 % raztopini NaCl. Ugotovljeno je bilo, da tesnjenje MAO nanosa z obdelavo v stearinski kislini, mo~no izbolj{a korozijsko odpornost aluminijeve zlitine 6061 v primerjavi z neobdelanim stanjem ali z nezatesnjenim MAO.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Formation of a corrosion-resistant alumina coating on a 6061 aluminum alloy using a combination of micro-arc oxidation and sealing treatments

Paksoy¹,

Muhaffel²,

Koca³

et al. 2017

Mater. Tehnol.

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“…X-ray analysis revealed principal peaks of the α-(alumina), β-and γ-Al 2 O 3 (corundum) phases within the oxide layers, hence the effect of substrate composition on micro-hardness is principally related to formation of these phases. Based on Debye-Sherrer measurements of the relevant XRD peaks 15 , corundum dominates the surface just below 150 V AC, while the amount of α-Al 2 O 3 increases with increasing voltage thereafter, due to the transformation of corundum to alumina in temperatures approaching 1000 °C 16,17 . The observed increase in micro-hardness as one moves from sample A3 to A1 can be explained on the basis of the γ-to α-Al 2 O 3 transformation.…”

Section: Resultsmentioning

confidence: 99%

Augmentation of wear-protective coatings for non-ferrous alloys by the addition of Cr and Ni elements

Antipas

2014

Mat. Res.

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“…While the literature regarding -Al 2 O 3 formation in MAO is not entirely unanimous, some observations can be made with respect to the different levels observed in the MAO and SMAO coatings. It has been previously noted that the accumulation of thermal energy in thicker coatings can help to generate the higher temperatures required to promote the → -Al 2 O 3 phase transition [25][26][27]. However, as phase changes normally require atomic rearrangement, the effect of time also needs to be considered.…”

Section: 5mentioning

confidence: 99%

Investigation of the Scanning Microarc Oxidation Process

Xia

Han

Domblesky

et al. 2017

Advances in Materials Science and Engineering

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Scanning microarc oxidation (SMAO) is a coating process which is based on conventional microarc oxidation (MAO). The key difference is that deposition in SMAO is achieved by using a stainless steel nozzle to spray an electrolyte stream on the substrate surface as opposed to immersing the workpiece in an electrolyzer. In the present study, SMAO discharge characteristics, coating morphology, and properties are analyzed and compared to results obtained from MAO under similar conditions. Results show that MAO and SMAO have comparable spark and microarc lifetimes and sizes, though significant differences in incubation time and discharge distribution were evident. Results also showed that the voltage and current density for MAO and SMAO demonstrate similar behavior but have markedly different transient and steady-state values. Results obtained from coating A356 aluminum sheet show that oxide thickness and growth rate in SMAO are strongly dependent on interelectrode spacing and travel speed. Analysis of the SMAO coating morphology and structure showed that a denser and slightly harder layer was deposited in comparison to MAO and is attributed to reduced porosity and increased formation of -Al 2 O 3 . Preliminary results indicate that SMAO represents a viable process for coating of aluminum surfaces.

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Characterization and wear- and corrosion-resistance of microarc oxidation ceramic coatings on aluminum alloy

Cited by 203 publications

References 14 publications

Formation of a corrosion-resistant alumina coating on a 6061 aluminum alloy using a combination of micro-arc oxidation and sealing treatments

Formation of a corrosion-resistant alumina coating on a 6061 aluminum alloy using a combination of micro-arc oxidation and sealing treatments

Augmentation of wear-protective coatings for non-ferrous alloys by the addition of Cr and Ni elements

Investigation of the Scanning Microarc Oxidation Process

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