Cerium-based conversion coatings to improve the corrosion resistance of aluminium alloy 6061-T6

Valdez, Benjamín; Kiyota, Sayuri; Stoytcheva, Margarita; Zlatev, Roumen; Bastidas, J. M.

doi:10.1016/j.corsci.2014.06.023

Cited by 137 publications

(61 citation statements)

References 69 publications

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“…H2O2 also oxidizes Ce 3+ ions to Ce 4+ in the solution by formation of a complex, provided that O2 is reduced at cathodic sites 45,54 :…”

Section: Morphology and Compositionmentioning

confidence: 99%

“…Most of the research on CeCC on aluminum alloys has been widely focused on protection of high strength alloys with aerospace applications such as AA2024 [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] and AA7075 20,[33][34][35][36][37][38][39][40] . Other studies include AA5083 12,[41][42][43] , AA6061 [44][45][46] , AA6063 47,48 and AA6082 49 .…”

Section: Introductionmentioning

confidence: 99%

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Deposition and Characterization of Cerium-Based Conversion Coating on HPDC Low Si Content Aluminum Alloy

Eslami¹,

Fedel²,

Speranza³

et al. 2017

J. Electrochem. Soc.

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Cerium-based conversion coatings were deposited on high pressure die cast (HPDC) Al-Si alloys using an immersion method. Hydrogen peroxide and sodium chloride were added to the conversion solution to accelerate the coating formation and to understand its formation mechanism. These studies showed that the deposition of cerium hydroxide/oxide conversion layer starts from iron-rich intermetallic particles, which are located inside the eutectic region and then the coating growth continues to cover the entire alloy surface. This phenomenon passivates the active interfaces between iron-rich intermetallic particles and/or the eutectic silicon phase and the aluminum matrix, which are prone to localized corrosion in chloride ions containing environments. Accordingly, values of the total impedance in EIS measurements significantly increased for the treated substrates. Morphologies of the conversion coatings and the oxidation state of cerium compounds were found to be dependent on the composition of the solution and the presence of chloride ions and/or hydrogen peroxide. Aluminum alloy with higher silicon content showed a more active surface during immersion in the conversion solution. This makes it more difficult to be treated using aggressive conversion solutions.

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“…H2O2 also oxidizes Ce 3+ ions to Ce 4+ in the solution by formation of a complex, provided that O2 is reduced at cathodic sites 45,54 :…”

Section: Morphology and Compositionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deposition and Characterization of Cerium-Based Conversion Coating on HPDC Low Si Content Aluminum Alloy

Eslami¹,

Fedel²,

Speranza³

et al. 2017

J. Electrochem. Soc.

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“…As shown in Figure 2, the corrosion resistance of coated aluminum increases up to 15-20 times in comparison to that of the bare aluminum. Valdes et al [31] demonstrated that the corrosion resistance of aluminum alloy 6061 increases in the presence of cerium-based coatings deposited by immersion method. They also showed that despite the presence of some cracks in the coatings, the corrosion resistance increased up to 20-30 times.…”

Section: Potentiodynamic Polarization Measurementsmentioning

confidence: 99%

Corrosion behavior of Ce-oxide/hydroxide coated AA7075-T6 prepared by dip immersion method

Danaee

Kanaani²,

Maddahy³

et al. 2014

Turkish J Eng Env Sci

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Abstract:In this study, cerium-based conversion coating was deposited on aluminum 7075-T6 by dip immersion method.Cerium oxide/hydroxide is an environmentally friendly conversion coating. Its corrosion resistance in 3.5 wt.% NaCl solution was investigated by means of electrochemical impedance spectroscopy, potentiodynamic polarization, and surface techniques. The coated samples showed a significant decrease in corrosion rate and the coating resistance increased with increasing immersion time up to 1200 s. In addition, electrochemical impedance data showed that in the presence of cerium oxide/hydroxide conversion coatings, the charge transfer resistance of aluminum increased. Surface morphology and its chemical composition were analyzed by means of scanning electron microscopy and energy dispersive spectroscopy.

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“…Then they were washed with ethanol and demineralized water and dried. Lanthanum and yttrium conversion coatings were performed by means of the galvanostatic technique at room temperature, using La(NO 3 …”

Section: Lanthanum-and Yttrium-conversion Coating Proceduresmentioning

confidence: 99%

“…These heterogeneities, mainly associated with the presence of intermetallic precipitations (IMs), are the source of localized corrosion when in contact with a corrosive environment. 3 Localized corrosion generally occurs in the form of pitting corrosion; it is initiated at discrete sites, in the vicinity of Fe-containing intermetallic phases of 6xxx aluminum alloys. [4][5][6][7][8] Metal impurities, even in small amounts, are can cause the formation of new phases, acting as cathodes in relation to the aluminum matrix.…”

Section: Introductionmentioning

confidence: 99%

Improvement of the corrosion behavior of aluminum alloy 6061-T6 with yttrium and lanthanum conversion coatings

Bekhiti¹,

Creus²,

Mesrati³

et al. 2018

Mater. Tehnol.

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In this study, yttrium-and lanthanum-based conversion coatings were deposited on a 6061-T6 aluminum alloy with cathodic electrochemical deposition using Y-and La-nitrate precursors. The optimum] ratio was evaluated with cyclic-voltammetry (CV) curves. The influence of the conversion-treatment time was studied by performing the experiment for periods of 10 and 20 minutes. Optical microscopy was used to determine the coating morphology and the anticorrosive properties were studied using linear polarization (LP) and electrochemical impedance spectroscopy (EIS) in a 5-g/L NaCl solution. The electrochemical results revealed an obvious improvement in the corrosion resistance against the aggressive media after an extended imersion test for 48 h, indicating a good efficiency of the Y-and La-conversion coating. Keywords: aluminum alloy, 6061-T6, conversion coating, rare earth elements, lanthanum, yttrium V pri~ujo~em~lanku avtorji opisujejo nanos konverzijske (pretvorbene) prevleke na osnovi itrija in lantana na Al zlitino 6061-T6 s katodno elektrokemijsko depozicijo (nanosom) z uporabo Y in La-nitratnih prekurzorjev (izhodnih surovin). S cikli~nimi voltametri~nimi (CV; angl.: Cyclic Voltammetry) krivuljami so ovrednotili optimalno razmerje[tudirali so vplive~asa na pretvorbo z izvedbo 10 in 20 minutnih preizkusov. S pomo~jo svetlobnega mikroskopa so podali morfologijo prevleke. S pomo~jo linearne polarizacije (LP) in elektrokemi~ne impedan~ne spektroskopije (EIS) v 5 g/L NaCl pa so {tudirali korozijsko odpornost prevleke. Rezultati elektrokemijskih preiskav so pokazali jasno izbolj{anje protikorozijske za{~ite v agresivnem mediju po podalj{anem 48 urnem potopnem preizkusu. To ka`e na dobro u~inkovitost izbrane obdelave za izdelavo Y in La pretvorbenih prevlek. Klju~ne besede: zlitina na osnovi aluminija, 6061-T6, pretvorbena prevleka, redki elementi zemlje, lantan, itrij

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Cerium-based conversion coatings to improve the corrosion resistance of aluminium alloy 6061-T6

Cited by 137 publications

References 69 publications

Deposition and Characterization of Cerium-Based Conversion Coating on HPDC Low Si Content Aluminum Alloy

Deposition and Characterization of Cerium-Based Conversion Coating on HPDC Low Si Content Aluminum Alloy

Corrosion behavior of Ce-oxide/hydroxide coated AA7075-T6 prepared by dip immersion method

Improvement of the corrosion behavior of aluminum alloy 6061-T6 with yttrium and lanthanum conversion coatings

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