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Dienstag, 14 Dezember 2021 13:00

Black Electrochemical Coatings for Aerospace and Allied Applications – Part 7 – Black Plasma Electrolytic Oxidation (PEO) Coatings

von
Geschätzte Lesezeit: 15 - 30 Minuten

Plasma electrolytic oxidation also known as micro arc oxidation (MAO) or spark anodization is a relatively new surface modification technique. The process is used for growing thick, and hard oxide coating on light metals and alloys such as Al, Mg, Ti [1-5]. In principle, the process is similar to anodizing but involves the use of higher voltages and is carried out with mild aqueous alkaline electrolytes [6–17]. In this process, plasma discharge occurs which leads to partial fusion of an oxide film and consequently formation of an extremely adhesive oxide coating on the substrate [18].

The PEO process is a rather inexpensive and environmentally friendly technique [19, 20]. The produced coatings possess very good wear and corrosion resistance as well as high thermal stability [21–23]. PEO coatings are employed in various engineering applications where very high corrosion and wear resistance, improved tribological and heat radiation characteristics are required such as pistons, cylinders, and hydraulic gear and variety of automobile and aerospace parts [24–26].

The mechanism of the PEO process can be divided into three stages, all the three stages occur simultaneously. The first stage involves oxide formation at metal-oxide interface. The second stage involves chemical dissolution of the oxide at oxide-electrolyte interface, and the third stage involves dielectric breakdown of the oxide layer at a high voltage. The dielectric breakdown produces millions of short-lived micro-discharges uniformly spread on the surface of the job creating a discharge channel for direct ejection of molten metal which is immediately oxidized, hydrolysed and precipitated on the workpiece [27–30].

At the discharge site chemical, electrochemical, thermo- dynamical, and plasma-chemical reactions occur to modify the structure, composition and morphology of PEO coatings [31]. As a result, mechanical properties such as wear resistance and toughness of the coating are enhanced [32–38]. PEO coating consists of three layers: a porous top layer, a dense intermediate layer with low porosity, and an inner transition layer. The dense inner layer acts as a good barrier layer for corrosion resistance and determines the thermo-mechanical and tribological properties of PEO coatings [5, 11, 29, 39–41]. The coating properties can vary strongly according to the alloy composition and process conditions [41]. The coating growth rate and porosity is dependent on electrolyte components, temperature, and characteristics of applied current.

The coating formation penetrates further into the free metal surface. Subsequent arcs are more likely to occur in other areas, where the oxide film is relatively thin. The discharges therefore have a natural tendency to preferentially thicken the thinnest regions of the film, resulting in fairly uniform film thickness, provided the electric field is fairly uniform. The porosity level in PEO coatings is generally higher. The pores observed are attributed to the entrapment of spherical gas bubbles [42, 43]. The macro- porosity on magnesium-based coatings is of the order of 40 %, however, the bulk of the film, in contrast, is quite dense.

The PEO process is carried out at room temperature in a very dilute and ecologically safe electrolyte. A typical electrolyte includes dilute solution of sodium or potassium hydroxides, silicates, phosphates or aluminates or mixture of these with several additives either to impart specific functional properties in the coating or to improve the coating growth process [44–57]. The PEO coating consists of oxide, silicate, fluoride, aluminate and phosphate, etc., based on the composition of electrolyte. The technological development, microstructural characteristics and applications of PEO process are reviewed elsewhere [3, 20, 24, 39, 41, 58–63].

The surface pre-treatment of PEO is much simpler when compared to anodization. Jobs can be processed for PEO coating just after careful solvent degreasing. The part to be coated is immersed in the electrolyte and is electrically connected in the electrochemical cell, so as to become one of the electrodes. The other counter-electrode is typically made from an inert material such as stainless steel, and often consists of the wall of the bath itself. The process can employ the continuous direct current or pulsed direct current or alternating pulses (pulsed unipolar and pulsed bi- polar). The PEO coating can be grown at the rate of about 1 µm per minute. Over 100 µm coating thickness can be easily grown on most of the substrates. After PEO coating parts are subjected to pores sealing in a demineralized water operating at > 95 °C (boiling) for 20–30 minutes.

Like aluminium anodizing, PEO coating at 15–45 μm thickness can behave as an effective radiator imparting good heat radiation properties. PEO coatings on AA6061 alloy were obtained with different concentrations of sodium silicate using positive uni-polar pulsed DC [64]. The process was optimized to obtain a solar reflector coating for spacecraft thermal control applications [65]. About ~40 μm thick PEO coating was found to provide maximum solar selectivity, where a solar absorptance of 0.37 and a thermal emittance of 0.81 was reported. The coatings were characterized using SEM, EDX, XRD, XPS, and nano profilometry and were subjected to simulated space environment testing.

The solar reflector, low absorbance and high emissivity, PEO coatings on Ti-6Al-4V alloy with silicate electrolytes were prepared by Zhongping Yao [66]. The concentration of silicate and the applied current density influence the thickness and the roughness of the coatings, and consequently the thermal control properties. The optimum results were exhibited with 10 g/L Na2SiO3 and 1 g/L NaH2PO2·H2O at a current density of 10 A/dm2, frequency: 500 Hz; time: 30 minutes; where a coating thickness of 80–100 µm resulted in a hemispherical emittance of 0.92 and a solar absorptance of 0.39 at 318 K. The coating is mainly composed of O, Si, Ti, P and Na. The PEO coating was porous with some big particles stacking around like large craters. It was not well crystallized and consisted of a large number of amorphous silicates.

The formation of black PEO coating on aluminium alloys using Keronite type process for space applications has been reported by Shrestha et al. [67–69]. A film thickness of 50–70 µm had an average solar absorptance value of 0.82 for AA7075 and 0.89 for AA2219, while the thermal emittance was 0.72. The coatings were subjected to space simulation (UV-exposure, thermal cycling, thermal shock) tests in vacuum and salt spray exposure. In accordance with ASTM D1654-92. The Keronite PEO samples displayed superior protection in salt spray environment (rating 10) than the hard-anodic coatings (rating 9). Wu et al. [70] have produced black PEO thermal control coating in a 0.1 mol/L sodium aluminate electrolyte. Experimental results showed that the coating can reach a solar absorptance value of 0.90 and an infrared emittance value >0.77. The optical properties and phase composition of the coating across the surface to the substrate-coating interface were studied by a spectrophotometer and X-ray diffraction.

The selection of the electrolyte in particular the incorporating of oxides of Fe, Co, Ni, W, Zr, Mn, Cr and V plays an important role in realization of various colours in the PEO coatings [71–84]. The coatings were gray-black and porous when Fe, Co, Ni and W from the electrolyte were incorporated into the coating.

Addition of metavanadate and tungstate in PEO electrolyte was found very encouraging in the formation of black PEO coatings [71–82]. Bayati et al. [72], have reported that the introduction of WO3 compounds into the PEO oxide coating would be effective to achieve the dark black colour WO3-Al2O3 composite films on the aluminium alloys. Surface morphology and topography of the layers were investigated. It was found that the composite layers had a porous structure with a rough surface. The layers consisted of γ-alumina, α-alumina, and tungsten trioxide phases, fractions of which varied with the applied voltage. The band gap of the composite layers was calculated as 3.42 eV using a UV-Vis spectrophotometer. Furthermore, photocatalytic performance of the synthesized composite layers was determined by measuring the decomposition rate of methylene blue solution on the surface of the layers.

A conformal black ceramic layer on aluminium alloy was fabricated by Hwang et al. [73] with an electrolyte containing 0.08 M sodium tungstate, 0.14 M potassium hydroxide and 0.05 M potassium hydrogen phosphate, operating at a current density of 10 A/dm2. A PEO coating was synthesized on an aluminium-silicon alloy containing 12 wt% Si with an electrolyte system containing sodium hexametaphosphate, [(NaPO3)6] as a conducting salt, and the effect of addition of ammonium metavanadate, [NH4VO3] on the surface morphology of PEO coating was investigated [74, 75]. It is difficult to form a uniform passive oxide layer on Al alloys with a high Si content due to the differences in the oxidation behaviour of the silicon-rich phase and the aluminium-rich phase. The addition of ammonium metavanadate to the electrolyte exhibited uniform black colour oxide coating on Si-rich aluminium alloy. The coating was characterized by XPS and confirmed to be a mixture of Al2O3, V2O3 and V2O5.

Li et al. [76] reported that when 6 g/L ammonium metavanadate is added to commonly used phosphate-silicate electrolyte [sodium hexametaphosphate, (NaPO3)6, 24g/L and sodium silicate Na2SiO3·9H2O, 15g/L; >40°C; 2 A/dm2; 15 minutes], the PEO coating changed its white appearance to black. Surface and cross-section morphology of the ceramic layer, in-layer concentration and chemical state of vanadium were investigated. Compared with the inner sublayer, an outer sublayer with a thickness of approximately 4μm formed on the surface which shows higher vanadium concentration. During the PEO process, the formation of metastable oxide phases provides active surfaces for the adsorption of VO3. The instantaneous high temperature in heat-affected zone around the discharge channel causes the transformation of adsorbed VO3 to vanadium oxide, such as V2O3 and V2O5. The formation of V2O3 results in the black colour of ceramic layer.

A uniform black PEO film was fabricated on hypoeutectic Al-Si alloy by employing a Na3PO4 electrolyte (0.04 mol/L), with different concentration of NH4VO3 and Na2WO4, and some NaOH (0.06-0.08 mol/L) to control the pH ~10 [77]. A bipolar pulse power supply was used where the positive voltage was increased from 100 to 400 V by nine steps, and the negative voltage was fixed at 30 V. The impulse frequency was 1 kHz, and the duty ratio was 30 %. It was observed that the distribution of the pores left by the discharge channels became more and more uniform with the processing time. The colour of the oxide layer changed from gray to brown gradually, and finally turned to black. The layer looks black due to existence of vanadium oxides and tungsten oxides on its surface. CIELAB colour space mode and colouring analysis demonstrated that the VO3 plays a more important role than WO42− in the colouring of PEO layer. The optimal colorant combination is 0.07 mol/L NH4VO3 and 0.06 mol/L Na2WO4 and a process time of 14 minutes.

In another method, Ma et al. [78] introduced pre-deposition of Sm0.5Sr0.5CoO3 microparticles to prepare the black PEO coating on AA6061. A layer of microparticles of grain size <10 µm, was first deposited on anodic substrate at 60 °C by gravity and then PEO coating was obtained in the electrolyte consisting of (NaPO3)6, 35 g/L and NaOH, 1.5 g/L; pH: 8.5; conductivity: 8.7 mS/cm; temperature: < 50 °C; frequency: 500 Hz; pulse width: 60 µs; current density: 0.8–1.6 A/dm2; time: 5–15 minutes. As the current density or time increased, the α decreased but ε increased. The resultant PEO coatings had a complex multiphase composition consisting of Sm2O3, SrAl4O7, AlPO4 and CoAl2O4 phases. The film imparted high solar absorptance, ≥ 0.85 and infrared emittance, ≥ 0.90. The surface characteristics of PEO layers on Mg alloy in phosphate electrolytes with and without ammonium metavanadate (NH4VO3) were examined by GunKo and co-workers [79]. PEO coatings were formed with KOH: 0.5 mol/L, K4P2O7: 0.15 mol/L with or without NH4VO3: 0.08 mol/L; solution conductivity (mS/cm): 61.8 and 55.1 with and without NH4VO3; current density: 10 A/dm2; coating time: 200 seconds. The temperature of electrolyte was maintained at 20 °C. With the addition of NH4VO3 to the electrolyte, the voltage profile changed significantly with the processing time. After 200 seconds, the size and number of micropores decreased and the colour of the PEO layer altered into black due to the incorporation of vanadium oxides (V2O3 and V2O5). The potentiodynamic polarization test in the 3.5 wt.% NaCl solution showed that the corrosion resistance of the PEO coatings greatly improved after incorporation of vanadium oxides.

A high absorptance and high emissivity black PEO coatings was prepared on Mg-Li alloy for thermal control application of spacecraft by Li et al. [80]. The PEO coatings appeared black in macroscopic scale, owing to the addition of vanadate in the electrolyte, and the coatings possessed typical porous structures with some protuberances in micron scale. The main element compositions of coatings were Mg, Si, V, O, Na and P, and most of them existed in form of amorphous phase, resulting from the quenching effect during the PEO coating formation process. The oxide of V mainly existed in the form of +3 valence (V2O3), which endow coatings with black appearance. With the increase of possessing time and vanadate concentration, the absorptance and emissivity of the coating were improved along with coating thickness. The optimal conditions include, 10 g/L of vanadate content and 10 minutes of process time, where the coatings reached an absorptance and emittance value of 0.964 and 0.951 respectively. The coatings possessed excellent thermal stability and corrosion resistance with promising application in aerospace.

Tu and team [81] have formed black PEO coatings on AZ31 magnesium alloy in an aluminate-tungstate electrolyte; NaAlO2: 10 g/L + Na2WO4·2H2O: 10 g/L + C6H8O7·H2O (citric acid): 3 g/L + KOH: 2 g/L; temperature: < 35 °C. Pulsed bipolar and unipolar regimes with a duty cycle of 20 % were employed with average positive and negative current densities being kept at ~22 and ~09 A/dm2, respectively. Coatings were fabricated at frequencies of 100, 1000 and 2000 Hz for durations up to 480 seconds. The micro-discharges were investigated by real-time imaging and photomultiplier methods. Coating colour was quantified by the CIELAB method. Blackness of PEO coatings depends on frequency and current regime. Coating‘s blackness was increased with frequency and tungsten incorporation and the blackest coatings obtained under unipolar regime at a frequency of 2000 Hz. Blacker coatings also revealed increased roughness and large internal pores, which were attributed to stronger plasma discharges and greater gas evolution.

A PEO process of flat absorber coating on Ti-6Al-4V alloy in phosphate electrolyte containing sodium tungstate was investigated by Zhongping Yao [82]. The top-notch results were obtained with Na5P3O10: 70 g/L, EDTA-2Na: 30 g/L, FeSO4: 15 g/L, Co(CH3COO)2: 15 g/L, Ni(CH3COO)2: 15 g/L and Na2WO4: 7.5 g/L. A pulsed current density of 1.5 A/cm2 was employed in a constant current regime with a working frequency of 1000 Hz for 25 minutes. The reaction temperature was controlled below 30 °C. Under these conditions, a solar absorptance of 0.93 and thermal emittance of 0.88 was achieved with a coating thickness of ~ 40 µm and roughness of ~1.3 µm. The annealing treatment was found to reduce the solar absorbance of the coating but it does not influence the emissivity, which may be associated with the improvement of the crystallization of PEO film.

REFERENCES

[1] A.L. Yerokhin; X. Nie; A. Leyland; A. Matthews; S.J. Dowey: Plasma electrolysis for surface engineering, Surf. Coat. Technol., 122(1999)2-3, 73–93, Doi: 10.1016/S0257-8972(99)00441-7
[2] Y. Zhang; W. Fan; H.Q. Du; Y.W. Zhao: Plasma electrolytic oxidation coatings for aluminum alloys, Mater. Performance, 56(2017)9, 38–41, www.researchgate.net/publication/320694309 
[3] E. Matykina; R. Arrabal; M. Mohedano; B. Mingo; J. Gonzalez; A. Pardo; M.C. Merino: Recent advances in energy efficient PEO processing of aluminium alloys, Trans. Nonferrous Met. Soc. China, 27(2017)7, 1439–1454, Doi: 10.1016/S1003-6326(17)60166-3
[4] J. Martin; A. Nomine; V. Ntomprougkidis; S. Migot; S. Bruyere; F. Soldera; T. Belmonte; G. Henrion: Formation of a metastable nanostructured mullite during plasma electrolytic oxidation of aluminium in Soft regime condition, Mater. Des., 180(2019), 10797, Doi: 10.1016/j.matdes.2019.107977
[5] F.C. Walsh; C.T.J. Low; R.J.K. Wood; K.T. Stevens; J. Archer; A.R. Poeton; A. Ryder: Plasma electrolytic oxidation (PEO) for production of anodised coatings on lightweight metal (Al, Mg, Ti) alloys, Trans. Inst. Met. Finish., 87(2009)3, 122–135, Doi: 10.1179/174591908X372482
[6] S. Shrestha; B.D. Dunn: Advanced plasma electrolytic oxidation treatment for protection of lightweight materials and structures in a space environment, Surface World, (2007), 40-44. esmat.esa.int/Publications/Published_papers/Keronite2007paper.pdf
[7] C. Mısırlı; M. Şahin; U. Sözer: Effect of Micro Arc Oxidation Coatings on the Properties of Aluminium Alloys (Chapter 4), Aluminium Alloys- New Trends in Fabrication and Applications, Zaki Ahmad (Editor), IntechOpen, (2013), 107–120, Doi: 10.5772/53135
[8] V. Dehnavi; B.L. Luan; X.Y. Liu; D.W. Shoesmith; S. Rohani: Correlation between plasma electrolytic oxidation treatment stages and coating microstructure on aluminum under unipolar pulsed DC mode, Surf. Coat. Technol., 269(2015), 91–99, Doi: 10.1016/j.surfcoat.2014.11.007
[9] R.O. Hussein; X. Nie; D.O. Northwood: An investigation of ceramic coating growth mechanisms in plasma electrolytic oxidation (PEO) processing, Electrochim. Acta, 112(2013), 111–119, Doi: 10.1016/j.electacta.2013.08.137
[10] Y. Pan; C. Chen; D. Wang; X. Yu: Microstructure and biological properties of micro‐arc oxidation coatings on ZK60 magnesium alloy, J Biomed. Mater. Res., 100B(2012), 1574–1586, Doi: 10.1002/jbm.b.32726
[11] G. Wirtz; S. Brown; W. Kriven: Ceramic coatings by anodic spark deposition, Mater. Manuf. Process., 6(1991), 87–115, Doi: 10.1080/10426919108934737
[12] H. Guo; M. An: Growth of ceramic coatings on AZ91D magnesium alloys by micro-arc oxidation in aluminate–fluoride solutions and evaluation of corrosion resistance, Appl. Surf. Sci., 246(2005)1–3, 229–238, Doi: 10.1016/j.apsusc.2004.11.031
[13] J. Liang; L. Hu; J. Hao: Improvement of corrosion properties of microarc oxidation coating on magnesium alloy by optimizing current density parameters, Appl. Surf. Sci. 253(2007)16, 6939–6945, Doi: 10.1016/j.apsusc.2007.02.010
[14] A. Ghasemi; V.S. Raja; C. Blawert; W. Dietze; K.U. Kainer: Study of the structure and corrosion behavior of PEO coatings on AM50 magnesium alloy by electrochemical impedance spectroscopy, Surf. Coat. Tech., 202(2008), 3513–3518, Doi: 10.1016/j.surfcoat.2007.12.033
[15] J. Liu; Y. Lu; X. Jing; Y. Yuan; M. Zhang: Characterization of plasma electrolytic oxidation coatings formed on Mg–Li alloy in an alkaline silicate electrolyte containing silica sol, Mater. Corros., 60(2009), 865–870, Doi: 10.1002/maco.200805204
[16] X. Wu, P. Su; Z. Jiang; S. Meng: Influences of Current Density on Tribological Characteristics of Ceramic Coatings on ZK60 Mg Alloy by Plasma Electrolytic Oxidation, ACS Appl. Mater. Interfaces, 2(2010)3, 808–812, Doi:10.1021/am900802x
[17] J. Cai; F. Cao; L. Chang; J. Zheng; J. Zhang; C. Cao: The preparation and corrosion behaviors of MAO coating on AZ91D with rare earth conversion precursor film, Appl. Surf. Sci., 257(2011)8, 3804–3811, Doi: 10.1016/j.apsusc.2010.11.153
[18] U. Malayoglu; K.C. Tekin; S. Shrestha: Influence of post-treatment on the corrosion resistance of PEO coated AM50B and AM60B Mg alloys, Surf. Coat. Tech., 205(2010)6, 1793–1798. Doi: 10.1016/j.surfcoat.2010.08.022
[19] P.G. Sheasby; R. Pinner: The Surface Treatment and Finishing of Aluminum and its Alloys, Vol. 1&2, 6th Edition, Finishing Publications/ ASM International, Materials Park, Ohio, (2001)
[20] G.B. Darband; M. Aliofkhazraei; P. Hamghalam; N. Valizade: Plasma electrolytic oxidation of magnesium and its alloys: Mechanism, properties and applications, J Magnesium Alloy, 5(2017)1, 74–132, Doi: 10.1016/j.jma.2017.02.004
[21] C. Blawert; W. Dietzel; E. Ghali; G. Song: Anodizing treatments for magnesium alloys and their effect on corrosion resistance in various environments, Adv. Eng. Mater. 8(2006)6, 511–533, Doi: 10.1002/adem.200500257
[22] Z.P. Yao; L.L. Li; X.R. Liu; Z.H. Jiang: Preparation of ceramic conversion layers containing Ca and P on AZ91D Mg alloys by plasma electrolytic oxidation, Surf. Eng., 26(2013)5, 317–320, Doi: 10.1179/174329409X409341
[23] R. Hussein; P. Zhang; X. Nie; Y. Xia; D. Northwood: The effect of current mode and discharge type on the corrosion resistance of plasma electrolytic oxidation (PEO) coated magnesium alloy AJ62, Surf. Coat. Tech., 206(2011)7, 1990–1997, Doi: 10.1016/j.surfcoat.2011.08.060
[24] B.L. Jiang; Y.M. Wang: Plasma electrolytic oxidation treatment of aluminium and titanium alloys (Chapter 5), Surface Engineering of Light Alloys. Aluminium, Magnesium and Titanium Alloys, Woodhead Publishing, Elsevier, (2010) 110–154
[25] V. Dehnavi; X.Y. Liu; B.L. Luan; D.W. Shoesmith; S. Rohani: Phase transformation in plasma electrolytic oxidation coatings on 6061 aluminum alloys, Surf. Coat. Technol., 251(2014), 106–114, Doi:10.1016/j.surfcoat.2014.04.010
[26] Q. Chen; W. Li; K. Ling; R. Yang: Investigation of growth mechanism of plasma electrolytic oxidation coating on Al-Ti double layer composite plate, Materials, 12(2019)2, 272, Doi: 10.3390/ma12020272
[27] J.A. Curran; H. Kalkanci; Yu Magurova; T.W. Clyne: Mullite-rich plasma electrolytic oxide coatings for thermal barrier applications, Surf. Coat. Technol., 201(2007)21, 8683–8687, Doi: 10.1016/j.surfcoat.2006.06.050
[28] T.W. Clyne; S.C. Troughton: A recent work on discharge characteristics during plasma electrolytic oxidation of various metals, Int. Mater. Rev., 64(2018)3, 127–162, Doi: 10.1080/09506608.2018.1466492
[29] W. Gebarowski; S. Pietrzyk: Influence of the cathodic pulse on the formation and morphology of oxide coatings on aluminum produced by plasma electrolytic oxidation, Arch. Metall. Mater., 58(2013)1, 241–245, Doi: 10.2478/v10172-012-0180-7
[30] E. Erfanifar; M. Aliofkhazraei; H.F. Nabavi; A.S. Roughaghdam: Growth kinetics and morphology of micro-arc oxidation coating on aluminum, Surf. Coat. Technol., 315(2017) 567–576, Doi: 10.1016/j.surfcoat.2017.03.002
[31] G. Sundararajan; L. Rama Krishna: Mechanisms underlying the formation of thick alumina coatings through the MAO coating technology, Surf. Coat. Technol., 167(2003)2–3, 269-277. Doi: 10.1016/S0257-8972(02)00918-0
[32] J. Curran; T.W. Clyne: Thermo-physical properties of plasma electrolytic oxide coatings on aluminium, Surf. Coat. Technol., 199(2005)2–3, 168–176, Doi: 10.1016/j.surfcoat.2004.09.037
[33] C.S. Dunleavy; I.O. Golosnoy; J. A. Curran; T.W. Clyne: Characterisation of discharge events during plasma electrolytic oxidation, Surf. Coat. Technol., 203(2009)22, 3410–3419, Doi: 10.1016/j.surfcoat.2009.05.004
[34] J. Curran; T. Clyne: The thermal conductivity of plasma electrolytic oxide coatings on aluminium and magnesium, Surf. Coat. Technol., 199(2005)2–3, 177–183, Doi: 10.1016/j.surfcoat.2004.11.045
[35] D.S. Tsai; C.C. Chou: Review of the soft sparking issues in plasma electrolytic oxidation, Metals, 8(2018)2, 1–22, Doi: 10.3390/met8020105
[36] E.A. Akbar; M.A. Qaiser; A. Hussain; R.A. Mustafa; D. Xiong: Surface modification of aluminum alloy 6060 through plasma electrolytic oxidation, Int. J Eng. Works, 4(2017)6, 114–123, Doi: hal.archives-ouvertes.fr/hal-01533006/document
[37] L.O. Snizhko; A.L. Yerokhin; A. Pilkington; N.L. Gurevina; D.O. Misnyankin; A. Leyland; A. Metthews: Anodic processes in plasma electrolytic oxidation of aluminum in alkaline solutions, Electrochim. Acta, 49(2014)13, 2085–2095, Doi: 10.1016/j.electacta.2003.11.027
[38] L. Agureev; S. Savushkina; A. Ashmarin; A. Borisov; A. Apelfeld; K. Anikin; N. Tkachenko; M. Gerasimov; A. Shcherbakov; V. Ignatenko; N. Bogdashkina: Study of plasma electrolytic oxidation coatings on aluminum composites, Metals, 8(2018)6, 459, Doi: 10.3390/met8060459
[39] Q. Li; J. Liang; Q. Wang: Plasma Electrolytic Oxidation Coatings on Lightweight Metals (Chapter 4), Modern Surface Engineering Treatments, M. Aliofkhazraei (Editor), IntechOpen, (2013) 75–99, Doi: 10.5772/55688
[40] X. Liu; S. Wang; N. Du; Q. Zhao: Evolution of the three-dimensional structure and growth model of plasma electrolytic oxidation coatings on 1060 aluminum alloy, Coatings, 8(2018)3, 105, Doi: 10.3390/coatings8030105
[41] R.O. Hussein; D.O. Northwood: Production of Anti-Corrosion Coatings on Light Alloys (Al, Mg, Ti) by Plasma-Electrolytic Oxidation (PEO) (Chapter 11), Developments in Corrosion Protection, M. Aliofkhazraei (Editor), IntechOpen, (2014) 201–239, Doi: 10.5772/57171
[42] O. Khaselev; D. Weiss; J. Yahalom: Anodizing of Pure Magnesium in KOH-aluminate Solutions under Sparking, J Electrochem. Soc., 146(1999)5, 1757–1761, Doi: 10.1149/1.1391838/pdf
[43] F.A. Bonilla; E. Berkani; Y. Liu; P. Skeldon; G.E. Thompson; H. Habazaki; K. Shimizu; C. John; K. Stevens: Formation of anodic films on magnesium alloys in an alkaline phosphate electrolyte, J Electrochem. Soc., 149(2002)1, B4–B13, Doi: 10.1149/1.1424896
[44] H.M. Wang; Z.H. Chen; L.L. Li: Corrosion resistance and microstructure characteristics of plasma electrolytic oxidation coatings formed on AZ31 magnesium alloy, Surf. Eng., 26(2010)5, 385–391, Doi: 10.1179/026708410X12506873242822
[45] P.B. Srinivasan; C. Blawert; M. Stormer; W. Dietzel: Characterisation of tribological and corrosion behaviour of plasma electrolytic oxidation coated AM50 magnesium alloy, Surf. Eng., 26(2010)5, 340–346, Doi: 10.1179/174329409X379246
[46] H.F. Guo; M.Z. An; H.B. Huo; S. Xu; L.J. Wu: Microstructure characteristic of ceramic coatings fabricated on magnesium alloys by micro-arc oxidation in alkaline silicate solutions, Appl. Surf. Sci., 252(2006)22, 7911–7916, Doi: 10.1016/j.apsusc.2005.09.067
[47] F. Jin; P.K. Chu; G. Xu; J. Zhao; D. Tang; H. Tong: Structure and mechanical properties of magnesium alloy treated by micro-arc discharge oxidation using direct current and high-frequency bipolar pulsing modes, Mater. Sci. Eng. A, 435–436(2006), 123–126, Doi: 10.1016/j.msea.2006.07.059
[48] Da Forno; M. Bestetti: Effect of the electrolytic solution composition on the performance of micro-arc anodic oxidation films formed on AM60B magnesium alloy, Surf. Coat. Technol., 205(2010)6, 1783–1788, Doi: 10.1016/j.surfcoat.2010.05.043
[49] A. Ghasemi; N. Scharnagl; C. Blawert; W. Dietzel; K.U. Kainer: Influence of electrolyte constituents on corrosion behaviour of PEO coatings on magnesium alloys, Surf. Eng., 26(2010)5, 321–327, Doi: 10.1179/026708408X344671
[50] D. Chen; W. Li; J. Jie: Investigation of the anti-corrosion ceramic coating formed on az91d magnesium alloy by micro-arc oxidation, Key Eng. Mater., 353-358(2007), 1645–1648, Doi: 10.4028/www.scientific.net/KEM.353-358.1645
[51] D. Sreekanth; N. Rameshbabu; K. Venkateswarlu: Effect of various additives on morphology and corrosion behavior of ceramic coatings developed on AZ31 magnesium alloy by plasma electrolytic oxidation, Ceram. Int., 38(2012)6, 4607–4615, Doi: 10.1016/j.ceramint.2012.02.040
[52] P.B. Srinivasan; J. Liang; C. Blawert; M. Stormer; W. Dietzel: Development of decorative and corrosion resistant plasma electrolytic oxidation coatings on AM50 magnesium alloy, Surf. Eng, 26(2010)5, 367–370, Doi: 0.1179/174329409X451155
[53] H.M. Wang; Z.H. Chen; Y.L. Cheng: Optimisation of anodising electrolyte for magnesium alloy AZ31 and characteristics of anodic film, Surf. Eng., 26(2010)5, 334–339, Doi: 10.1179/026708409X363219
[54] H. Zhao; Z. Liu; Z. Han: A Comparison on Ceramic Coating Formed on AM50 Alloy by Micro-Arc Oxidation in Two Electrolytes, Mater. Sci. Forum, 546-549, (2007) 575–578, Doi: 10.4028/www.scientific.net/MSF.546-549.575
[55] T. Harikrishna; A. Rajendra; A.K. Sharma: A Process for forming a corrosion resistant oxide coating on magnesium alloys, Indian Patent 295, 389, (2012)
[56] D. Veys-Renaux; C.-E. Barchiche; E. Rocca: Corrosion behavior of AZ91 Mg alloy anodized by low-energy micro-arc oxidation: Effect of aluminates and silicates, Surf. Coat. Technol., 251(2014) 232–238, Doi: 10.1016/j.surfcoat.2014.04.031
[57] X.M. Song; G. Yu; H.B. Yi; L.Y. Ye; B.N. Hu: Phosphate-silicate composite coating formed on AM60 magnesium alloy, Surf. Eng., 26(2010)5, 371–377, Doi: 10.1179/026708409X12450792800114
[58] P. Zhang; X. Nie; H. Hu; Y. Liu: TEM analysis and tribological properties of Plasma Electrolytic Oxidation (PEO) coatings on a magnesium engine AJ62 alloy, Surf. Coat. Technol., 205(2010)5, 1508–1514, Doi: 10.1016/j.surfcoat.2010.10.015
[59] V.K. Patel; S. Bhowmik: Plasma processing of aluminum alloys to promote adhesion: A critical review, Rev. Adhesion Adhesives, 5(2017)1, 79–104, Doi: 10.7569/RAA.2017.097303
[60] L. Famiyeh; X. Huang: Plasma electrolytic oxidation coatings on aluminum alloys: Microstructures, properties, and applications, Modern Concept Mater. Sci., 2(2019)1, 1–13, Doi: 10.33552/MCMS.2020.02.000526
[61] B.V. Vladimirov; B.L. Krit; V.B. Lyudin; N. V. Morozova; A. D. Rossiiskaya; I. V. Suminov; A.V. Epel’feld: Microarc Discharge Oxidizing of Magnesium Alloys: A Review, Surf. Eng. Appl. Electrochem., 50(2014), 195–232, Doi: 10.3103/S1068375514030090
[62] Ao Ni; D. Liu; X. Zhang; He Guangyu: Microstructural characteristics of PEO coating: Effect of surface nanocrystallization. J Alloys Compds., 823 (2020), 153823, Doi: 10.1016/j.jallcom.2020.153823.
[63] F. Simchen; M. Sieber; A. Kopp; T. Lampke: Introduction to plasma electrolytic oxidation-An overview of the process and applications, Coatings, 10(2020)7, 628. Doi: 10.3390/coatings10070628
[64] A.M. Pillai; A. Rajendra; A.K. Sharma: Influence of process parameters on growth behaviour and properties of coatings obtained by plasma electrolytic oxidation (PEO) on AA 6061, J Appl. Electrochem., 48(2018), 543–557, Doi: 10.1007/s10800-018-1186-2
[65] A.M. Pillai; A. Rajendra; A.K. Sharma; S. Sampath: Development of a solar reflector coating on AA6061 alloy by plasma electrolytic oxidation, J Appl. Electrochem., 49(2019), 1239–1254, Doi: 10.1007/s10800-019-01362-7
[66] Zhongping Yao; Qiaoxiang Shen; Aoxiang Niu; Bing Hu; Zhaohua Jiang: Preparation of high emissivity and low absorbance thermal control coatings on Ti alloys by plasma electrolytic oxidation, Surf. Coat. Technol., 242(2014), 146–151, Doi: 10.1016/j.surfcoat.2014.01.034
[67] S. Shrestha; A. Merstallinger; D. Sickert; B.D. Dunn: Some preliminary evaluations of black coating on aluminium AA2219 alloy produced by plasma electrolytic oxidation (PEO) process for space applications, Proc. 9th Int Symposium on Materials in a Space Environment, Noordwijk, The Netherlands, 16-20 June 2003 (ESA SP-540), September 2003, 57–66
[68] S. Shrestha; P. Shashkov; B.D. Dunn: Microstructural and thermo-optical properties of black Keronite PEO coating on aluminium alloy AA7075 for spacecraft materials applications, Proc. 10th ISMSE & 8th ICPMSE, Collioure, France, 19-23 June 2006 (ESA SP-616, September 2006). http://esmat.esa.int/Materials_News/SP-16/session_01/S1_5_Shrestharev.pdf
[69] S. Shrestha; B.D. Dunn: Plasma electrolytic oxidation and anodising of aluminium alloys for spacecraft applications (Chapter 18), Surface Engineering of Light Alloys-Aluminium, Magnesium and Titanium Alloys, Woodhead Publishing, Elsevier, (2010), 603-641
[70] X. Wu; W. Qin; B. Cui; Z. Jiang; W. Lu: Black ceramic thermal control coating prepared by microarc oxidation, Int. J Appl. Ceram. Technol., 4(2007)3, 269–275, Doi: 10.1111/j.1744-7402.2007.02140.x
[71] G.E. Thompson; F. Monfort; E. Matykina; A. Berkani; P. Skeldon: Coating generation by spark anodizing of light alloy, Corros. Rev., 25(2007)5-6, 631–650, Doi: 10.1515/CORRREV.2007.25.5-6.631
[72] M.R. Bayati; H. Zargar; R. Molaei; F. G. Fard; E. Kajbafvala; S. Zanganeh: One step growth of WO3-loaded Al2O3 micro/nano-porous films by micro arc oxidation, Colloids Surf. A: Physicochem. Eng. Asp., 355(2010)1–3, 187–192, Doi: 10.1016/j.colsurfa.2009.12.018
[73] I.J. Hwang; K.R. Shin; J.S. Lee; Y.G. Ko; D.H. Shin: Formation of black ceramic layer on aluminum alloy by plasma electrolytic oxidation in electrolyte containing Na2WO4, Mater. Trans., 53(2012)3, 559–564, Doi: 10.2320/matertrans.M2011263
[74] I.J. Hwang; D.Y. Hwang; Y. M. Kim; B. Yoo; D. H. Shin: Formation of uniform passive oxide layers on high Si content Al alloy by plasma electrolytic oxidation, J Alloy. Compd., 504(2010)Suppl.1, S527–S530, Doi: 10.1016/j.jallcom.2010.02.074
[75] Y.M. Kim; D.Y. Hwang; C.W. Lee; B. Yoo; D. H. Shin: Surface modification of high Si content Al alloy by plasma electrolytic oxidation, Kor. J Met. Mater., 48(2010), 49–56, Doi: 10.3365.KJMM.2010.48.01.049
[76] J. Li; H. Cai; B. Jiang: Growth mechanism of black ceramic layers formed by microarc oxidation, Surf. Coat. Technol., 201(2007), 8702–8708, Doi: 10.1016/j.surfcoat.2007.06.010
[77] K. Li; W. Li; G. Zhang; P. Guo: Preparation of black PEO layers on Al-Si alloy and the colorizing analysis, Vacuum, 111(2015), 131–136, Doi: 10.1016/j.vacuum.2014.10.008
[78] Delin Ma; Chunhua Lu; Zhenggang Fang; Weigang Yan; Ling Wei; Yaru Ni; Zhongzi Xu: Preparation of high absorbance and high emittance coatings on 6061 aluminum alloy with a pre-deposition method by plasma electrolytic oxidation, Appl. Surf. Sci., 389(2016), 874–881, Doi: 10.1016/j.apsusc.2016.08.011
[79] Y. Gun Ko; K.M. Lee; D. Hyuk Shin: Effect of ammonium metavanadate on surface characteristics of oxide layer formed on Mg alloy via plasma electrolytic oxidation, Surf. Coat. Technol., 236(2013), 70–74, Doi: 10.1016/j.surfcoat.2013.08.060 
[80] X. Li; Q. Xia; C. Chen; Z. Yao: Preparation of high absorptance and high emissivity coatings on Mg-Li alloy by plasma electrolytic oxidation, Meter. Res. Express, 6(2019)10, 106428, Doi: 10.1088/2053-1591/ab3d8d 
[81] W. Tu; W. Zhu; X. Zhuang; Y. Cheng; P. Skeldon: Effect of frequency on black coating formation on AZ31 magnesium alloy by plasma electrolytic oxidation in aluminate-tungstate electrolyte, Surf. Coat. Technol., 372(2019), 34–44, Doi: 10.1016/j.surfcoat.2019.05.012 
[82] Zhongping Yao; Bing Hu; Qiaoxiang Shen; Aoxiang Niua; Zhaohua Jiang; Peibo Su; Pengfei Ju: Preparation of black high absorbance and high emissivity thermal control coating on Ti alloy by plasma electrolytic oxidation, Surf. Coat. Technol., 253(2014), 166–170, Doi: 10.1016/j.surfcoat.2014.05.032 
[83] J.-M. Wang; D.-S. Tsai; J.T.J. Tsai; C.C. Chou: Coloring the aluminum alloy surface in plasma electrolytic oxidation with the green pigment colloid, Surf. Coat. Technol., 321(2017), 164–170, Doi: 10.1016/j.surfcoat.2017.04.038 
[84] D. Y. Hwang; Y. M. Kim; D. Y. Park; B. Yoo; D. H. Shin: Corrosion resistance of oxide layers formed on AZ91 Mg alloy in KMnO4 electrolyte by plasma electrolytic oxidation, Electrochim. Acta, 54(2009)23, 5479–5485, Doi: 10.1016/j.electacta.2009.04.047

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  • Ausgabe: 12
  • Jahr: 2021
  • Autoren: Dr. Anand Kumar Sharma

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