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Phase transformation in plasma electrolytic oxidation coatings on 6061 aluminum alloy

Published on Jul 1, 2014in Surface & Coatings Technology 3.19
· DOI :10.1016/j.surfcoat.2014.04.010
Vahid Dehnavi5
Estimated H-index: 5
(UWO: University of Western Ontario),
Xing Yang Liu7
Estimated H-index: 7
(National Research Council)
+ 2 AuthorsSohrab Rohani35
Estimated H-index: 35
(UWO: University of Western Ontario)
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Abstract
Abstract Oxide coatings were produced on a 6061 aluminum alloy using a pulsed unipolar plasma electrolytic oxidation (PEO) process. The effect of electrical parameters including pulse frequency, duty cycle and current density on phase formation in the coatings was revealed using conventional and glancing angle X-ray diffraction. The results show that PEO coatings are mainly composed of γ-Al 2 O 3 . Depending on the electrical parameters employed, the coatings can also contain α-Al 2 O 3 and mullite with varying concentrations. Higher current densities and higher duty cycle were found to favor the formation of mullite. Under the experimental conditions used, the ratio of the integrated XRD peaks for α- and γ-Al 2 O 3 varied from 0 to about 0.6, indicating that the relative content of α-Al 2 O 3 in the PEO coatings varied over a wide range. Longer pulse on-times and higher current densities promoted the gamma to alpha-alumina phase transformation. Depth profiling of PEO ceramic coatings using glancing angle XRD with different incident beam angles revealed that mullite was more concentrated in the top surface of the coatings. No significant variation in α-Al 2 O 3 concentration across the coatings could be concluded in this study, unlike the results of some other studies.
  • References (46)
  • Citations (41)
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References46
Newest
Published on Jan 1, 2014in Vacuum 2.52
Shen Dejiu3
Estimated H-index: 3
(Technology College),
Cai Jingrui2
Estimated H-index: 2
(Technology College)
+ 6 AuthorsYang Yaqian1
Estimated H-index: 1
(Technology College)
Abstract Non-uniform microstructure and low growth rate of ceramic coatings in the mid-to late period of micro-arc oxidation (MAO) are the problems that limit the development of micro-arc oxidation technology. In this paper, the MAO process on 6061 aluminum alloy was carried out under ultrasonic condition, and the effects of ultrasonic vibration on microstructure and growth characteristics of MAO coatings were investigated. The results showed that the ultrasonic action obviously promoted the for...
Published on Jan 1, 2014in Ceramics International 3.45
Shuyan Wang1
Estimated H-index: 1
(Jiangsu University),
Yongping Xia1
Estimated H-index: 1
(Jiangsu University)
+ 1 AuthorsNaichao Si1
Estimated H-index: 1
(Jiangsu University)
Abstract Ceramic coatings were obtained on AZ91D magnesium alloy by microarc oxidation under unipolar and bipolar modes in a silicate–aluminate dual electrolyte. The surface and cross-sectional morphology, coating thickness and phase composition of coatings were characterized by scanning electron microscopy (SEM), layer thickness meter and X-ray diffraction (XRD), respectively. The corrosion resistance of coatings in a 3.5% NaCl neutral solution was evaluated by electrochemical impedance spectro...
Published on Sep 1, 2013in Electrochimica Acta 5.38
Ying Liang Cheng1
Estimated H-index: 1
(Hunan University),
Zhigang Xue3
Estimated H-index: 3
(Hunan University)
+ 4 AuthorsG.E. Thompson41
Estimated H-index: 41
(University of Manchester)
Abstract Coatings have been produced on an 2A97 Al–Cu–Li alloy by plasma electrolytic oxidation (PEO) using dilute and concentrated sodium silicate solutions with pulsed electrical regimes. Brownish red coatings were formed, especially in the dilute silicate solution. The colour is attributed to cuprite, formed by oxidation of copper in the alloy. The main phases of the coatings formed in the dilute and concentrated electrolytes are γ-Al 2 O 3 and mullite, respectively. A bi-layer coating is for...
Published on Jul 1, 2013in Surface & Coatings Technology 3.19
Vahid Dehnavi5
Estimated H-index: 5
(UWO: University of Western Ontario),
Ben Li Luan4
Estimated H-index: 4
(UWO: University of Western Ontario)
+ 2 AuthorsSohrab Rohani35
Estimated H-index: 35
(UWO: University of Western Ontario)
Abstract Ceramic coatings were created on the surface of 6061 aluminum alloy using a plasma electrolytic oxidation (PEO) process employing a pulsed direct current (DC) power mode in an alkaline electrolyte. The effect of electrical parameters including frequency and duty cycle on the microdischarge behavior and coating growth was investigated at constant current. Surface features of coatings were studied using scanning electron microscopy. Energy dispersive spectroscopy was employed to investiga...
Published on Nov 1, 2012in Journal of Alloys and Compounds 4.17
R.O. Hussein1
Estimated H-index: 1
(U of W: University of Windsor),
Derek O. Northwood37
Estimated H-index: 37
(U of W: University of Windsor),
Xueyuan Nie30
Estimated H-index: 30
(U of W: University of Windsor)
Abstract Plasma electrolytic oxidation (PEO) is an electrochemical process uses an environmentally-friendly aqueous electrolyte to oxidize the metal surfaces to form ceramic oxide coatings which impart a high corrosion and wear resistance. In this study we investigated the effect of current mode on the properties of PEO coatings formed on an AM60B magnesium alloy. Unipolar, bipolar and hybrid (combination of both) current modes were used in this work. Optical emission spectroscopy (OES) was empl...
Published on Jun 1, 2012in Corrosion Science 6.36
Yingliang Cheng13
Estimated H-index: 13
(Hunan University),
Fan Wu2
Estimated H-index: 2
(Hunan University)
+ 2 AuthorsG.E. Thompson41
Estimated H-index: 41
(University of Manchester)
Abstract Plasma electrolytic oxidation coatings were formed in alkaline silicate electrolyte on Zircaloy-2. The evolution of the types of discharges, the microstructures, phase compositions and the corrosion resistance of the coatings were studied by real time imaging, SEM, XRD, and electrochemical tests. Characteristic solidification structures were revealed in the PEO coatings, the formation of the solidification structures is related to the long lasting discharges during the PEO process and t...
Published on Dec 1, 2011in Materials Characterization 3.22
Mehmet Tarakci7
Estimated H-index: 7
(GIT: Gebze Institute of Technology)
Abstract The binary Al–Mg synthetic alloys were prepared in a vacuum/atmosphere controlled furnace with the addition of 0.5, 1, 2, 4, 7, and 15 wt.% pure Mg into pure aluminum as substrate material. The surfaces of the Al–Mg alloys and pure aluminum were coated for 120 min by plasma electrolytic oxidation in the same electrolyte of 12 g/L sodium silicate and 2 g/L KOH in distilled water. The coating was characterized by X-ray diffraction, scanning electron microscopy, profilometry and Vickers mi...
Published on Aug 1, 2011in Materials & Design 5.77
T. Abdulla2
Estimated H-index: 2
(University of Sheffield),
Aleksey Yerokhin21
Estimated H-index: 21
(University of Sheffield),
Russell Goodall20
Estimated H-index: 20
(University of Sheffield)
Abstract Plasma Electrolytic Oxidation (PEO) coating treatment is applied to open celled aluminium foams with different structures, aiming to enhance the mechanical performance of the composite material. The mechanical properties of the coated foams produced are assessed experimentally, both in tension and compression. From experimental results, yield stress is found to increase initially with increasing PEO coating thickness, though this trend is not maintained with thicker coatings. This is ca...
Published on Mar 1, 2011in Surface & Coatings Technology 3.19
Chih-Hsiang Hsu1
Estimated H-index: 1
(NCHU: National Chung Hsing University),
Huan-Ping Teng1
Estimated H-index: 1
,
Fu-Hsing Lu19
Estimated H-index: 19
(NCHU: National Chung Hsing University)
Abstract Alumina coatings were prepared by plasma electrolytic oxidation (PEO) on Al alloys using NaAlO 2 electrolytes with added Al(NO 3 ) 3 to enhance the mechanical properties of the coatings. Electrolytes (0.1 M NaAlO 2 ) with small amounts of Al(NO 3 ) 3 ranging from 1.0 to 5.3 mM were employed at a fixed current density (10 A/dm 2 ). With the added Al(NO 3 ) 3 , the onset of spark discharges was delayed, which is associated with the dissolution and oxidation of Al alloys in the nitrates. X...
Published on Dec 1, 2010in Surface & Coatings Technology 3.19
R.H.U. Khan5
Estimated H-index: 5
(University of Birmingham),
A.L. Yerokhin16
Estimated H-index: 16
(University of Sheffield)
+ 2 AuthorsA. Matthews60
Estimated H-index: 60
(University of Sheffield)
Abstract Plasma electrolytic oxidation (PEO) is a specialised but well-developed process which has found applications in aerospace, oil/gas, textile, chemical, electrical and biomedical sectors. A novel range of coatings having technologically attractive physical and chemical properties (e.g. wear- and corrosion-resistance) can be produced by suitable control of the electrolyte as well as electrical parameters of the PEO process. Oxide ceramic films, 3 to 40 μm thick, were produced on 6082 alumi...
Cited By41
Newest
Published on Jul 1, 2019in Applied Surface Science 5.16
A.C. Bouali1
Estimated H-index: 1
,
E.A. Straumal (RAS: Russian Academy of Sciences)+ 7 AuthorsMikhail L. Zheludkevich45
Estimated H-index: 45
(CAU: University of Kiel)
Abstract This work reports a novel approach for growing layered double hydroxide (LDH) films on any plasma electrolytic oxidation (PEO) coated AA2024 independently of the nature of the PEO coating. The specific PEO coating chosen to carry out this work is considered to be not suitable for direct LDH growth because of phase composition and morphological features. In this paper, we describe a new methodology that consists of covering the PEO coating with a thin layer of aluminum oxide based xeroge...
Published on Oct 1, 2019in Materials & Design 5.77
Julien Martin7
Estimated H-index: 7
(University of Lorraine),
Alexandre Nomine6
Estimated H-index: 6
(University of Lorraine)
+ 5 AuthorsGérard Henrion13
Estimated H-index: 13
(University of Lorraine)
Abstract This paper demonstrates the possibility of producing a lamellar ceramic nanocomposite at the top-most surface of oxide coatings grown with the Plasma Electrolytic Oxidation process (PEO). PEO was conducted on aluminium in a silicate-rich electrolyte under the so-called “soft” regime. Nanoscale characterisation showed that the transition from the “arcs” to the “soft” regime was concomitant with the gradual formation of a 1:1 mullite/alumina lamellar nanocomposite (≈120 nm thick) that fil...
Published on May 1, 2019in Applied Surface Science 5.16
Golsa Mortazavi2
Estimated H-index: 2
,
Golsa Mortazavi (UTA: University of Texas at Arlington)+ 0 AuthorsE. I. Meletis39
Estimated H-index: 39
Abstract A critical parameter in Plasma Electrolytic Oxidation (PEO) is the applied current composed of electronic current caused by sparking and ionic current caused by diffusion of electrolyte ions into the oxide. A wide spectrum of current densities was applied on pure titanium to investigate the PEO mechanism. The growth process and oxide characteristics were investigated by studying the ionic/electronic current contributions during the PEO stages. The contribution of electronic current was ...
Published on Jul 1, 2019in International Journal of Adhesion and Adhesives 2.50
S. Aliasghari1
Estimated H-index: 1
,
S. Aliasghari (University of Manchester)+ 1 AuthorsMohammad Ghorbani24
Estimated H-index: 24
Abstract A study has been carried out of the effect of plasma electrolytic oxidation (PEO) on the strength of AA 5052 alloy/polypropylene joints prepared using friction stir spot welding (FSSW). The joint strengths were determined using lap-shear tests and failure modes were investigated using scanning electron microscopy. Comparisons were made between control joints prepared with the alloy in the as-rolled condition or the as-rolled condition with a mechanical key and with PEO-treated alloy, wi...
Published on Jun 1, 2019in Journal of Cleaner Production 6.39
Carime dos Santos Souza (UNESP: Sao Paulo State University), Maria Lúcia Pereira Antunes7
Estimated H-index: 7
(UNESP: Sao Paulo State University)
+ 2 AuthorsNilson Cristino da Cruz14
Estimated H-index: 14
(UNESP: Sao Paulo State University)
Abstract Exhaust dust is a solid byproduct resulting from the casting process. With the aim of finding an alternative use for this residue, evaluation was made of the possibility of producing ceramic coatings with the material. Coatings on 5052 aluminum alloys were obtained by the electrolytic plasma technique, using an electrolytic solution prepared with exhaust powder and distilled water (5 g/L). The electrolytic plasma was obtained by applying a potential difference of 650 V and frequency of ...
Published on May 1, 2019in Radiation Measurements 1.44
Aleksejs Zolotarjovs5
Estimated H-index: 5
(LU: University of Latvia),
K. Smits10
Estimated H-index: 10
(LU: University of Latvia)
+ 5 AuthorsLinards Skuja28
Estimated H-index: 28
(LU: University of Latvia)
Abstract For decades, plasma electrolytic oxidation (PEO) coatings are actively studied and applied to protect the surface of various valve metals from chemical or mechanical damage. However, over the last couple of years intense research is being done to explore additional possibilities of the PEO coatings apart from their classical application. One of the possible additional uses is thermostimulated luminescence dosimetry that is already widely applied for environmental and health monitoring. ...
Published on Apr 1, 2019in Journal of materials research and technology 3.33
Matheus de M. Tavares , Jussier de Oliveira Vitoriano3
Estimated H-index: 3
+ 4 AuthorsClodomiro Alves-Júnior4
Estimated H-index: 4
Abstract Plasma electrolytic oxidation (PEO) is an environmentally friendly anodizing technique that produces ceramic coatings using high voltage discharges. To the present work this technique was applied to treat aluminum surfaces using a pulsed current supply and sodium silicate electrolyte. The effect of the duty cycle and treatment time on the morphology, phase composition and tribo-mechanical properties of the formed layer was investigated. The current density was maintained at 12 A/dm 2 , ...
PEO ceramic coatings including ZrO2-Al2O3-SiO2 in three phases were prepared on an Al- 12.5%Si alloy in electrolyte solutions containing ZrO2 nanoparticles. The microstructures and phases of the coatings were analyzed by SEM and XRD, and the heat insulation performance and the thermal shock resistance of the coatings were investigated. The compactness of the coating increased significantly and the hindrance of the Si element on plasma electrolytic oxidation process was effectively weakened. The ...