Corrosion resistance and microstructure of electrodeposited Zn and Zn alloy coatings

Ramanauskas, R.; Quintana, P.; Maldonado, L.; Pomés, R.; Pech‐Canul, M. A.

doi:10.1016/s0257-8972(96)03125-8

Cited by 122 publications

(55 citation statements)

References 27 publications

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“…These results show that the corrosion performance of these electrodeposits is superior to that of plain Zn coatings. [1][2][3][4][5][6][7][8][9][10][11][12] An important aspect, from a practical and technological standpoint, is that these coatings must still have a high Zn content to maintain the cathodic protection of the steel substrate while still remaining less active than just Zn coatings. Additionally, due to environmental and health considerations, these zinc alloy coatings have been proposed as potential candidates to replace highly carcinogenic Cd coatings in anticorrosive applications.…”

Section: Introductionmentioning

confidence: 99%

“…16 On the other hand, the literature offers little data about the understanding of the corrosion mechanism of Zn-Co coatings, stating only that the Co content in the layer is about 1% (wt.%) and that corrosion tests so far have been based only on short term laboratory aging tests such as salt spray and potentiodynamic electrochemical polarization. [2][3][4][5][6][7][9][10][11][12][13] However, these kinds of laboratory tests can lead to different corrosion mechanisms of the Zn-alloy coatings when compared with the corrosion mechanism of the coatings exposed to the natural atmosphere, as reported in the literature for electrodeposited Zn-Ni alloys. 8 A previous study showed that the corrosion mechanism of Zn-Fe coatings presented a good correlation between a long-term total immersion laboratory test in NaCl solution and a natural exposing test in marine atmosphere for 3 years.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Corrosion study of electrodeposited Zn and Zn-Co coatings in chloride medium

Lima‐Neto¹,

Correia²,

Colares³

et al. 2007

J. Braz. Chem. Soc.

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A corrosão de eletrodepósitos de Zn e Zn-Co em solução aquosa de NaCl 0.1 mol dm -3 foi investigada usando as técnicas de microscopia eletrônica de varredura (SEM), energia dispersiva de raios-X (EDX), dissolução anódica sob controle galvanostático (GES), impedância eletroquímica (EIS) e medidas de potencial de circuito aberto (E oc ). Todos os eletrodepósitos foram feitos sobre aço carbono. Fases intermetálicas foram identificadas nas camadas de ZnCo com teor de Co superior a 1 at.%. Os resultados de GES, SEM e EDX mostraram que o mecanismo de corrosão das camadas de Zn-Co com mais alto teor de Co está relacionado ao surgimento de trincas devido à dissolução de fases intermetálicas ricas em Zn, enquanto que a corrosão das camadas de Zn e Zn-1Co foi caracterizada pela dissolução destas. Os produtos de corrosão identificados foram os mesmos em todas as camadas testadas, os quais atuaram como barreira, mas não foram capazes de prevenir o processo corrosivo. A melhor resistência à corrosão das camadas de Zn-Co obtidas a partir do banho não aditivado, em comparação à camada de Zn-1Co obtida do banho aditivado, é devido ao elevado teor de Co que promove um enobrecimento da camada. Todas as camadas de Zn-Co apresentaram resistência à corrosão superior às camadas de Zn. A camada Zn-18Co apresentou o melhor desempenho anticorrosivo com uma durabilidade 3 vezes superior a camada de Zn.The corrosion behavior of electrodeposited Zn and Zn-Co coatings in 0.1 mol dm -3 NaCl aqueous solutions was investigated using scanning electron microscopy (SEM), energy dispersive X-ray (EDAX), galvanostatic electrochemical stripping (GES), electrochemical impedance spectroscopy (EIS) techniques and open circuit measurements (E oc ). All coatings were electrodeposited on mild steel. Using GES it was possible to identify Zn-Co intermetallic phases in the coatings with Co content higher than 1 at.%. The GES, SEM and EDX results revealed that the corrosion mechanism of the Zn-Co layers with high Co content is related to the appearance of cracks due to the dissolution of the γ Zn-rich phases, while the corrosion of the Zn and Zn1Co layers was characterized by dissolution of the coatings. The Zn and Zn-Co coatings were found to contain the same insoluble corrosion products, which act as a corrosion barrier that delays but does not prevent corrosion. The better corrosion resistance of the Zn-Co coatings obtained in the bath without additive, in comparison with Zn-1Co obtained in the bath containing additive is due to the high Co content which leads to an ennoblement of the coating. All Zn-Co electrodeposits showed greater corrosion resistance than the Zn electrodeposits. The Zn-18Co layer showed the best corrosion resistance, with a lifetime about three times longer than that of the Zn layer.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Corrosion study of electrodeposited Zn and Zn-Co coatings in chloride medium

Lima‐Neto¹,

Correia²,

Colares³

et al. 2007

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…Zinc and zinc alloys (ZnCo, ZnNi) are widely used in the corrosion protection of steel. [2][3][4][5][6][7][8] But these zinc alloys exhibit a significantly higher corrosion resistance than pure zinc coating. [9][10][11][12][13][14][15][16] Conducting polymers like polyaniline, polythiophene and polypyrrole have shown wide range of applications due to their very interesting physical properties.…”

Section: Introductionmentioning

confidence: 99%

Poly(N-methylpyrrole) Film on ZnNi Plated Carbon Steel Electrode

Akdag

Özyılmaz

2017

ACSi

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In this study, zinc-nickel (ZnNi) particles were electrochemically deposited on carbon steel (CS) electrode applying constant current of 1 mA with chronopotentiometry technique. Poly(N-methylpyrrole) (PNMP) film on CS/ZnNi electrode was synthesized with cyclic voltammetry technique from 0.10 M N-methylpyrrole containing 0.20 M sodium oxalate solution. The corrosion performances of coated and uncoated electrodes in 3.5% NaCl solution were evaluated with the help of AC impedance spectroscopy (EIS) and anodic polarisation curves. Scanning electron microscopy (SEM) and linear sweep voltammetry (LSV) were used to characterization of coatings. It was shown that the ZnNi particles exhibited important barrier effect on CS substrate. The highest 298350 ohm value of polarization resistance showed that PNMP film on the CS/ZnNi electrode exhibited an effective barrier property and electrocatalytic behaviour protection of substrate for longer exposure time.

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“…Zn coatings are well known to be used as protective layers on steel sheets because of their good corrosion-protection performance, with electrogalvanized coatings having homogeneous surface reactivity [1][2][3]. Steel sheets with protective Zn coatings are widely used in automotive body panels, electric appliances [4,5], and building materials [6].…”

Section: Introductionmentioning

confidence: 99%

X-ray photoelectron and scanning Auger electron spectroscopy study of electrodeposited ZnCr coatings on steel

et al. 2012

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Zn-Cr alloyed coatings electrochemically deposited are of high interest for leading steel manufacturing companies because of their novel properties and high corrosion resistance compared with conventional Zn coatings on steel. For tuning and optimizing the properties of the electrodeposited Zn-Cr coatings, a broad range of the deposition conditions must be studied. For this reason, two different types of material were investigated in this study, one with a low electrolyte temperature and one with an elevated electrolyte pH, compared with the standard values. Because different corrosion performance and delamination behaviour of the layers were observed for the two types, advanced surface analysis was conducted to understand the origin of this behaviour and to discover differences in the formation of the coatings. The topmost surface, the shallow subsurface region, and the whole bulk down to the coating-steel interface surface were analysed in detail by X-ray photoelectron spectroscopy (XPS) and high-resolution scanning Auger electron spectroscopy to determine the elemental and the chemical composition. For better understanding of the resulting layer structure, multiple reference samples and materials were measured and their Auger and XPS spectra were fitted to the experimental data. The results showed that one coating type is composed of metallic Zn and Cr, with oxide residing only on the surface and interface, whereas the other type contains significant amounts of Zn and Cr oxides throughout the whole coating thickness.

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Corrosion resistance and microstructure of electrodeposited Zn and Zn alloy coatings

Cited by 122 publications

References 27 publications

Corrosion study of electrodeposited Zn and Zn-Co coatings in chloride medium

Corrosion study of electrodeposited Zn and Zn-Co coatings in chloride medium

Poly(N-methylpyrrole) Film on ZnNi Plated Carbon Steel Electrode

X-ray photoelectron and scanning Auger electron spectroscopy study of electrodeposited ZnCr coatings on steel

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