Electrochemical Behavior of Chemical Vapor Deposited Protective Aluminum Oxide Coatings on Ti6242 Titanium Alloy

Boisier, Grégory; Răciulete, Monica; Samélor, Diane; Pébère, Nadine; Gleizes, Alain; Vahlas, Constantin

doi:10.1149/1.2968109

Cited by 15 publications

(18 citation statements)

References 8 publications

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“…The data presented in Variation of the oxide layer composition results in a change in chemical reactivity of the oxide with the chloride ion and its porosity, and thereafter corrosion resistance. 8, 47 The results presented in ref. [8] suggest that transformation of the surface oxide film into the AlO(OH) phase 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 enhances the passivity of the Al surface, and thereafter corrosion resistance in a chloride solution.…”

Section: Resultsmentioning

confidence: 92%

Synergistic Effect of Superhydrophobicity and Oxidized Layers on Corrosion Resistance of Aluminum Alloy Surface Textured by Nanosecond Laser Treatment

Бойнович

Emelyanenko

Модестов

et al. 2015

ACS Appl. Mater. Interfaces

209

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We report a new efficient method for fabricating a superhydrophobic oxidized surface of aluminum alloys with enhanced resistance to pitting corrosion in sodium chloride solutions. The developed coatings are considered very prospective materials for the automotive industry, shipbuilding, aviation, construction, and medicine. The method is based on nanosecond laser treatment of the surface followed by chemisorption of a hydrophobic agent to achieve the superhydrophobic state of the alloy surface. We have shown that the surface texturing used to fabricate multimodal roughness of the surface may be simultaneously used for modifying the physicochemical properties of the thick surface layer of the substrate itself. Electrochemical and wetting experiments demonstrated that the superhydrophobic state of the metal surface inhibits corrosion processes in chloride solutions for a few days. However, during long-term contact of a superhydrophobic coating with a solution, the wetted area of the coating is subjected to corrosion processes due to the formation of defects. In contrast, the combination of an oxide layer with good barrier properties and the superhydrophobic state of the coating provides remarkable corrosion resistance. The mechanisms for enhancing corrosion protective properties are discussed.

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Section: Resultsmentioning

confidence: 92%

Synergistic Effect of Superhydrophobicity and Oxidized Layers on Corrosion Resistance of Aluminum Alloy Surface Textured by Nanosecond Laser Treatment

Бойнович

Emelyanenko

Модестов

et al. 2015

ACS Appl. Mater. Interfaces

209

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“…The lower current densities obtained for the coated sample is attributed to the higher thickness of the alumina film. The amorphous alumina deposited on SS surface modifies the cathodic reaction due to a pronounced barrier effect which limits the oxygen reduction [17,26,27].…”

Section: Electrochemical Measurementsmentioning

confidence: 99%

“…before crystallization of the amorphous film takes place) were shown, thus allowing the replacement of e.g. SS by titanium alloys in hotter parts of aeroturbines [15][16][17][18]. The promising performance of the amorphous alumina was attributed to the absence of grain boundaries in the coating and to the reduced oxygen vacancy diffusion in alumina [19].…”

Section: Introductionmentioning

confidence: 99%

“…The promising performance of the amorphous alumina was attributed to the absence of grain boundaries in the coating and to the reduced oxygen vacancy diffusion in alumina [19]. Electrochemical measurements revealed that amorphous Al 2 O 3 coatings processed at 480°C provide the best performance, with a two orders of magnitude improvement of the corrosion resistance with regard to the bare titanium alloy [17].…”

Section: Introductionmentioning

confidence: 99%

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Corrosion protection of 304L stainless steel by chemical vapor deposited alumina coatings

et al. 2014

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The corrosion protection of 304L stainless steel by aluminium oxide coatings deposited by metal-organic chemical vapor deposition (MOCVD) was investigated in a 0.1 M NaCl solution at room temperature by polarization curves and electrochemical impedance spectroscopy. The effect of the coating thickness was specifically considered. Transmission electron microscopy cross-section observations of the stainless steel/alumina coating showed that the coating is amorphous and porosity-free. The impedance response, for short immersion times, confirmed the absence of porosity and revealed that the alumina coatings with thickness ranging from 250 nm to 1700 nm provide high corrosion resistance. The corrosion protection increased when the alumina coating thickness increased. However, from the impedance data obtained for different exposure times to the aggressive solution, a threshold film thickness of 500-600 nm was determined, above which the corrosion protection was not improved. Due to their interesting physicochemical properties, such films of amorphous alumina are an innovative and economically accessible alternative to improve the stainless steel corrosion resistance and could be used in miniaturized sensors operating in marine environment. c-Al 2 O 3 takes place. Deposition temperature also impacts the composition of the films: combined electron probe microanalysis (EPMA), Rutherford backscattering spectroscopy (RBS) and energy-dispersive X-ray spectroscopy (EDS) showed that, for films processed at 350°C, the O/Al ratio is equal to 2. For these films, Fourier transform infrared spectrometry (FTIR) revealed the presence of OH groups, with the overall composition corresponding to that of aluminium oxy-hydroxide, AlOOH. With increasing deposition temperature, the O/Al ratio and the concentration of OH groups gradually decrease to reach a composition which matches

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“…In parallel, promising barrier properties were demonstrated for such amorphous coatings, especially for the protection of titanium alloys from oxidation and corrosion at temperatures up to 600 8C. [4][5][6] These works revealed that, despite its instability and trend to ageing, ATI can be used for reproducibly depositing aluminum oxide provided that it is stored in a glove box, and renewed in the bubbler after a few hours of use. The next step towards industrial implementation of this process is the insight into the involved chemical reactions, and the determination of the corresponding reaction kinetics.…”

mentioning

confidence: 98%

Local Kinetic Modeling of Aluminum Oxide Metal‐Organic CVD From Aluminum Tri‐isopropoxide

Vergnes

Samélor

Gleizes

et al. 2011

Chemical Vapor Deposition

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Due to numerous allotropic modifications and to the subsequent large spectrum of structure-properties relationships, aluminum oxides in the form of films and coatings are of major technological interest for a wide range of applications, e.g., optics and microelectronic components, wear resistance, catalyst support, protection against corrosion, and high temperature oxidation. Metal-organic (MO)CVD is a potentially attractive technique for the processing of such coatings, especially on complex-in-shape, temperature-sensitive parts. In this context, processingstructure relationships were established and the feasibility of such a process was proven, on the laboratory scale, in a series of papers recently published by the authors. [1][2][3] It is recalled that, using aluminum tri-isopropoxide (ATI) as the precursor and operating in a hot-wall reactor in the temperature range 350-415 8C, under 5 Torr, with dry N 2 as a carrier/dilution gas results in partially hydroxylated films AlO 1þx (OH) 1-2x ; x varies from 0 (AlOOH) at 350 8C to 0.5 (Al 2 O 3 ) at 415 8C. Films processed between 415 8C and 650 8C are composed of amorphous Al 2 O 3 ; nanostructured gamma-alumina films are obtained at a deposition temperature of 700 8C. In parallel, promising barrier properties were demonstrated for such amorphous coatings, especially for the protection of titanium alloys from oxidation and corrosion at temperatures up to 600 8C. [4][5][6] These works revealed that, despite its instability and trend to ageing, ATI can be used for reproducibly depositing aluminum oxide provided that it is stored in a glove box, and renewed in the bubbler after a few hours of use. The next step towards industrial implementation of this process is the insight into the involved chemical reactions, and the determination of the corresponding reaction kinetics. Such knowledge allows process modeling, and hence controlling, and consequently optimizing, the relation between macroscopic processing conditions and the local deposition rates.There are very few reports on local kinetic modeling of the MOCVD processes. This blank spot in processing science is due to the often complex chemical mechanisms involved, combining poorly known homogeneous and heterogeneous chemical reactions. The main difficulty then is to find representative chemical reactions and the related kinetic laws. Concerning the MOCVD of alumina from ATI, Kawase et al. experimentally investigated reaction kinetics in a hot-wall tubular reactor under 30 Torr total pressure in the temperature range 830-1160 8C.[7] Assuming a firstorder reaction in ATI, they found an activation energy of 179 kJ mol À1 . They also obtained different deposition rates in two different tubular reactor diameters and concluded that the dominant reaction mechanism was the homogeneous pyrolysis of ATI. Hofman et al. performed CVD and mass spectroscopic experiments in this system operating under 3 Torr between 220 8C and 450 8C.[8] The authors showed that propene is a deposition by-product, and that the rate-limiting step...

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Electrochemical Behavior of Chemical Vapor Deposited Protective Aluminum Oxide Coatings on Ti6242 Titanium Alloy

Cited by 15 publications

References 8 publications

Synergistic Effect of Superhydrophobicity and Oxidized Layers on Corrosion Resistance of Aluminum Alloy Surface Textured by Nanosecond Laser Treatment

Synergistic Effect of Superhydrophobicity and Oxidized Layers on Corrosion Resistance of Aluminum Alloy Surface Textured by Nanosecond Laser Treatment

Corrosion protection of 304L stainless steel by chemical vapor deposited alumina coatings

Local Kinetic Modeling of Aluminum Oxide Metal‐Organic CVD From Aluminum Tri‐isopropoxide

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