Microstructural characteristics of cerium oxide conversion coatings obtained by various aqueous deposition methods

Johnson, Benedict; Edington, Joe; Williams, Alexander Mitchell; O’Keefe, Matthew J.

doi:10.1016/j.matchar.2004.10.006

Cited by 74 publications

(79 citation statements)

References 10 publications

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“…Deposition and corrosion properties of CeCC have been studied not only on aluminum alloys but also on other such as magnesium alloys [5][6][7][8] and steel [9][10][11][12] . 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%

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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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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“…These coatings also can provide the required adhesion with the final top coat. Chromate converting coatings are effective and inexpensive corrosion inhibitors [16,17], however these coatings are toxic and carcinogenic due to presence of hexavalent chromium [16][17][18][19][20][21]. So European Union has forbidden the use of these inhibitors in 2000.…”

Section: Introductionmentioning

confidence: 99%

Deposition and corrosion behavior of silicate conversion coatings on aluminum alloy 2024

Kazemi

Danaee

Zaarei

2014

Materialwissenschaft Werkst

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Potassium silicate was deposited on AA2024 aluminum alloy as environmentally friendly conversion coatings and its corrosion behavior were examined by means of electrochemical impedance spectroscopy, potentiodynamic polarization and surfaces techniques. Potentiodynamic polarization curves show significant decrease in corrosion current density of silicate coated aluminum in NaCl solution. The corrosion resistance was increased with increasing silicate concentration of coating baths. The results indicated that the coating applied from 3 molar silicate baths is more uniform and continuous. The X-ray diffraction (XRD) and energy discharge spectroscopy (EDS) spectra confirm the existence of silicate film on the AA2024 surface. The coating performance was evaluated in acidic and basic NaCl solution and the results show the stability of silicate conversion coating in these solutions.

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“…It is clearly indicated that the coating was composed of nano-crystalline particles with a sphere-like morphology. SAED patterns measured d-spacings of the three distinguishable rings could neither be indexed nor matched closely to any of the oxides ( [17]. Figure 5 shows HRTEM micrographs of Ce-rich particles.…”

Section: Corrosion Behaviormentioning

confidence: 97%

Surface treatment of Cf/Al composites with immersion in aqueous solution containing Ce ions for corrosion barrier

Wang

Chen

2009

Materials & Corrosion

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In this study, Ce-rich coating is investigated as corrosion inhibitor of carbon fibers reinforcement aluminum matrix (Cf/Al) composites. The coatings are obtained by immersion in aqueous solution containing Ce(NO 3 ) 3 onto composite surface, whereas the Ce-rich coating process produces a coating with highly heterogeneous nature of the surface, but micro-cracked layer with ''dry-mud'' morphology. The coatings were composed of Ce-rich nano-particles, Ce-rich particles with a sphere-like morphology, which are agglomerated particles with diameter 4 $ 8 nm and piled up for this coating. TEM observation for Ce conversion coating of the corresponding ring-like SAED patterns could not be matched to any of the previously reported structures of cerium compounds. Results of high-resolution XPS spectra of Ce3d obtained for Ce conversion coating show that the Ce3d spectra has several components with binding energies characteristic of Ce 3þ and Ce 4þ . The Ce-rich coating process produces effective corrosion protecting of Cf/Al composites, which is verified by electrochemical measurement results. The R t values of coated sample are higher than those of uncoated sample, this confirms the better corrosion resistance of coating obtained after immersion treatment for Cf/Al composites.

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Microstructural characteristics of cerium oxide conversion coatings obtained by various aqueous deposition methods

Cited by 74 publications

References 10 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

Deposition and corrosion behavior of silicate conversion coatings on aluminum alloy 2024

Surface treatment of Cf/Al composites with immersion in aqueous solution containing Ce ions for corrosion barrier

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