Dissolution of cerium from cerium-based conversion coatings on Al 7075-T6 in 0.1M NaCl solutions

Joshi, Simon; Kulp, Elizabeth A.; Fahrenholtz, William G.; O’Keefe, Matthew J.

doi:10.1016/j.corsci.2012.03.023

Cited by 51 publications

(28 citation statements)

References 30 publications

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“…The corrosion inhibition mechanism of REE is often attributed to the deposition of an insoluble passive RE oxide/hydroxide film at cathodic domains [4,8], facilitated by the alkaline pH which arises from the reduction of water and/or oxygen [9]. The failure mechanism of these conversion coatings have been generally attributed to penetration of corrosive species (e.g.…”

Section: Introductionmentioning

confidence: 99%

Corrosion protection afforded by praseodymium conversion film on Mg alloy AZNd in simulated biological fluid studied by scanning electrochemical microscopy

Jamali

Moulton

Tallman

et al. 2015

Journal of Electroanalytical Chemistry

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Surface passivation of AZNd Mg alloy with Pr(NO 3 ) 3 is studied using scanning electrochemical microscopy (SECM) in surface generation/tip collection (SG/TC) and AC modes. Corrosion protection afforded by the Pr treatment and the degradation mechanism in a simulated biological environment was examined on a local scale and compared with non-treated AZNd. SG/TC mode results revealed a drastic decrease in H2 evolution due to the Pr treatment. Mapping the local insulating characteristics using AC-SECM showed higher conductivity of the surface where H 2 evolution was most favorable. Keywordsscanning, studied, fluid, biological, simulated, corrosion, microscopy, protection, electrochemical, afforded, praseodymium, conversion, film, mg, alloy, aznd Disciplines Engineering | Physical Sciences and Mathematics Publication DetailsJamali, S. S., Moulton, S. E., Tallman, D. E., Forsyth, M., Weber, J., Mirabedini, A. & Wallace, G. G. (2015). Corrosion protection afforded by praseodymium conversion film on Mg alloy AZNd in simulated biological fluid studied by scanning electrochemical microscopy. Journal of Electroanalytical Chemistry, 739 211-217. AuthorsSeyed S. Jamali, Simon E. Moulton, Dennis E. Tallman, Maria Forsyth, Jan Weber, Azadehsadat Mirabedini, and Gordon G. Wallace AbstractSurface passivation of AZNd Mg alloy with Pr(NO 3 ) 3 is studied using scanning electrochemical microscopy (SECM) in surface generation/tip collection (SG/TC) and AC modes. Corrosion protection afforded by the Pr treatment and the degradation mechanism in a simulated biological environment was examined on a local scale and compared with nontreated AZNd. SG/TC mode results revealed a drastic decrease in H 2 evolution due to the Pr treatment. Mapping the local insulating characteristics using AC-SECM showed higher conductivity of the surface where H 2 evolution was most favorable.

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Section: Introductionmentioning

confidence: 99%

Corrosion protection afforded by praseodymium conversion film on Mg alloy AZNd in simulated biological fluid studied by scanning electrochemical microscopy

Jamali

Moulton

Tallman

et al. 2015

Journal of Electroanalytical Chemistry

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“…Therefore, in the last decades, it has been attempted to replace them with the more environmentally friendly alternatives. 14,[21][22][23] Spinel anticorrosive pigments have been developed via doping metal oxide with inhibitive components. [24][25][26][27][28] They showed both barrier and inhibitive actions when embedded in the organic coatings.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical investigation of the epoxy nanocomposites containing MnAl2O4 and CoAl2O4 nanopigments applied on the aluminum alloy 1050

et al. 2015

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The MnAl 2 O 4 and CoAl 2 O 4 nanopigments were synthesized through solution combustion method. The nanopigments extracts in the 3.5 wt% NaCl solution were prepared. Electrochemical impedance spectroscopy (EIS) and linear polarization (LP) techniques were utilized to investigate the corrosion inhibition properties of the pigments in the solutions containing pigments extracts. The epoxy nanocomposites were prepared and applied on the aluminum specimens. EIS and pull-off measurements were performed to characterize the corrosion protection properties of the epoxy nanocomposites. It was revealed that the MnAl 2 O 4 pigment showed higher corrosion inhibition properties than CoAl 2 O 4 in the solution phase. In addition, MnAl 2 O 4 enhanced the corrosion resistance and decreased the adhesion loss of the epoxy coating on the aluminum substrate significantly. The MnAl 2 O 4 nanopigment improved the corrosion resistance of the epoxy coating through increasing the barrier performance and releasing inhibitive species.

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“…In this context, the advantage of cerium based sealing is to provide a film with high corrosion resistance, without employing toxic chemicals and using a relatively fast process. [43][44][45][46] In a previous work, the sealing response of the traditional TSA cycle to the three sealing conditions was investigated in detail and some of the data presented here are taken from there 47 for the purpose of comparison with the response of the modified TSA cycle.…”

Section: C908mentioning

confidence: 99%

Cerium-Based Sealing of Anodic Films on AA2024T3: Effect of Pore Morphology on Anticorrosion Performance

Carangelo

Curioni

Acquesta

et al. 2016

J. Electrochem. Soc.

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In this work, porous anodic oxides were produced by traditional and modified tartaric sulfuric anodizing (TSA) processes and sealed in hot water, chromate and cerium based solutions. The sealing behavior of a film with relatively coarse porosity, generated at high voltage (traditional TSA), was compared to the sealing behavior of a film with finer porosity and generated at reduced potential (modified TSA). After sodium chromate sealing, the two anodizing cycles produced film with similar anticorrosion performance. Conversely, after hot water or cerium sealing, the finer oxides generated at low voltage (modified TSA) provided much better corrosion resistance. EIS performed in-situ during sealing revealed that chromate sealing is very aggressive to the porous skeleton compared to the other sealing treatments. Therefore, the original morphology has little effect on the final performance, since both fine and coarse oxides are substantially attacked. In contrast, the oxide morphology has a substantial effect when sealing is performed in hot water or cerium-based solution. Overall, it is possible to obtain films with anticorrosion performance equivalent or improved compared to that obtained by traditional TSA anodizing cycle sealed with chromate by combining the low voltage anodizing cycle with the cerium-based sealing. Aerospace aluminum alloys display outstanding mechanical properties but require specific protection measures in order to meet the requirements of durability and corrosion resistance. Anodizing in acidic electrolytes is one of the methods that are most widely employed for this purpose, since it produces porous oxides that improve corrosion resistance and adhesion with organic coatings.The porous anodic oxide morphology generated on high copper alloys is significantly different from that generated on high purity aluminium.1-3 Specifically, on aluminum, anodizing in phosphoric, sulfuric, or oxalic acid, results in the generation of a well-ordered oxide morphology, comprising closely-packed hexagonal cells with a central cylindrical pore, and having a diameter that is proportional to the applied potential.4-10 Under these conditions, the pore walls are generally straight and uniform (provided that anodizing is conducted under steady applied potential or current). At the bottom of the pores, close to the metal, a barrier layer is observed with thickness proportional to the applied potential. On the other hand, the thickness of the porous oxide is proportional to the charge passed. Due to the dependence of barrier layer thickness and pore diameter on the applied potential, and to the dependence of the film thickness on charge, porous morphologies can be tailored by controlling the electrical regime (potential-time or current-time), and complex morphologies can be achieved to enhance specific properties.11-14 It has been shown that fine pores and thick films are beneficial for corrosion protection.13 However fatigue life can be an issue for aerospace alloys 15 and therefore film thickness should be limited to...

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Dissolution of cerium from cerium-based conversion coatings on Al 7075-T6 in 0.1M NaCl solutions

Cited by 51 publications

References 30 publications

Corrosion protection afforded by praseodymium conversion film on Mg alloy AZNd in simulated biological fluid studied by scanning electrochemical microscopy

Corrosion protection afforded by praseodymium conversion film on Mg alloy AZNd in simulated biological fluid studied by scanning electrochemical microscopy

Electrochemical investigation of the epoxy nanocomposites containing MnAl2O4 and CoAl2O4 nanopigments applied on the aluminum alloy 1050

Cerium-Based Sealing of Anodic Films on AA2024T3: Effect of Pore Morphology on Anticorrosion Performance

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