Evaluation of the corrosion behavior of galvannealed steel in chloride aqueous solution and in tropical marine environment

Silva, Paulo S. G. da; Costa, A. J.; Mattos, O.R.; Correia, Adriana N.; Lima‐Neto, Pedro de

doi:10.1007/s10800-005-9083-x

Cited by 22 publications

(12 citation statements)

References 18 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%

“…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. 1 In the industrial plating process, the low Co content in the electrodeposited Zn-Co layer (≅ 1% / wt.%) is associated to the presence of commercial additives in the plating solutions, such as levelers or brighteners, because the use of additives makes it possible to obtain layers with a decorative appearance. Industrial additives contain complexing agents that form stable complexes with cobalt ions that hinder the cobalt deposition.…”

Section: Introductionmentioning

confidence: 99%

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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.

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“…19 The GA layer before the electrochemical dissolution showed the presence of stick crystal, which is a characteristic of the zeta phase, and columnar crystal, which is typical of the delta phase. 18 According to XRD results, which were obtained in a previous work, the delta phase is predominant in galvanneal layer (62.3% of counts per second), followed by the gamma (27.6%) and zeta (10.1%) phases. 15 In the coulometric dissolution, each phase dissolves at a characteristic potential, which was in a range between 2860 and 2855 mV(SCE) for the zeta phase, 2808 and 2798 mV(SCE) for the delta phase and between 2721 and 2716 mV(SCE) for the gamma phase.…”

Section: Discussionmentioning

confidence: 79%

Corrosion resistance of Fe–Zn surfaces of galvannealed steel revealed after coulometric stripping in acid, alkaline and saline media

Lins

Batista

Castro

et al. 2016

Corrosion Engineering, Science and Technology

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The corrosion of galvannealed steel revealed three different Fe-Zn surfaces on the steel substrate, and each surface showed a different corrosion behaviour in a given environment. In order to evaluate the corrosion behaviour of each revealed surface, the electrochemical impedance spectroscopy (EIS) technique was performed in acid, alkaline and saline media containing chlorides and sulphates. The Mossbauer spectroscopy was also used to elucidate the iron phases on each surface, and these results identified the delta phase on all surfaces obtained after coulometric dissolution of galvannealed steels. In the hydrochloric acid and sodium chloride solution, the outer surface richest in zinc showed the highest polarisation resistance among the surfaces obtained using coulometric stripping of galvannealed steel, and the corrosive process occurred on the electrode surface. In the alkaline solution, the inner layer showed the highest polarisation resistance among the surfaces obtained after dissolution of galvannealed steel, and the equivalent circuit fitted to the EIS data is characteristic of a corrosion of a porous layer.

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“…47,48 The latter is related to the diffusion of the zinc oxidation products to the bulk solution or to oxygen reduction. 11,[48][49][50] Associated with the decrease in impedance modulus in mid-and lowfrequency regions is a decrease and shift of the phase angle of the first time-constant toward lower frequencies and a decrease of the phase angle of the second time-constant. This can be related to the decreased corrosion resistance of the reference system.…”

Section: Resultsmentioning

confidence: 99%

A Complementary Electrochemical Approach for Time-Resolved Evaluation of Corrosion Inhibitor Performance

Meeusen¹,

Zardet²,

Homborg³

et al. 2019

J. Electrochem. Soc.

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In this paper, different macroscopic electrochemical techniques are applied to study the corrosion inhibitor efficiency, protection mechanism and stability of a calcium aluminum polyphosphate silicate hydrate inhibitor on hot-dip galvanized steel in the timedomain. Potentiodynamic polarization (PP) measurements are applied to study the anodic and cathodic mechanistic behavior as well as inhibitor efficiencies at discrete and single times of exposure. Open circuit potential (OCP) with superimposed linear polarization resistance (LPR) measurements are applied as a faster, non-invasive alternative to PP, characterizing the overall performance of the system in terms of the polarization resistance. Electrochemical impedance spectroscopy (EIS) measurements are applied to detail both the overall performance of the system as well as the corrosion inhibition mechanism related to the electrochemical system's physicochemical representation over time. Electrochemical noise (EN) measurement are used to evaluate the inhibition efficiency as a function of exposure time, represented by the electrochemical noise resistance. Odd random phase electrochemical impedance spectroscopy (ORP-EIS) is selected as the electrochemical tool to study the system's instability, by evaluation of the non-linearities and non-stationarities over time. The non-stationarities present in the inhibitor-containing electrochemical system are shown to cause the overall instability of the system and should be taken into account when interpreting results from the different techniques over time.

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Evaluation of the corrosion behavior of galvannealed steel in chloride aqueous solution and in tropical marine environment

Cited by 22 publications

References 18 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

Corrosion resistance of Fe–Zn surfaces of galvannealed steel revealed after coulometric stripping in acid, alkaline and saline media

A Complementary Electrochemical Approach for Time-Resolved Evaluation of Corrosion Inhibitor Performance

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