Atmospheric corrosion evaluation of electrogalvanized, hot-dip galvanized and galvannealed interstitial free steels using accelerated field and cyclic tests

Alvarenga, Evandro de Azevedo; Lins, Vanessa de Freitas Cunha

doi:10.1016/j.surfcoat.2016.04.021

Cited by 25 publications

(12 citation statements)

References 36 publications

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“…Firstly, 30 to 60 min of reaction produce coatings 2 to 3 times thicker than commercial GA coatings. Secondly, epanized parts show excellent paint-ability; paint adheres very well on Fe-Zn compounds; and the organic coating hinders the migration of the oxidizing molecules to the coating [8,11,16,17]. The excellent adhesion probably results from the chemical composition and the natural small-scale roughness of the epanized layers.…”

Section: Discussionmentioning

confidence: 99%

“…It is worth noting that no special priming treatment (nor sand blasting) is required before painting the epanized steel. Thirdly, on one hand, the Fe-Zn compounds are very efficient in preventing paint delamination upon corrosion at scribes, because the Fe-Zn compounds are zinc-rich, so that zinc-corrosion products diffuse, passivate and heal scratches [16,17]. On the other hand, the electrochemical potentials of Fe-Zn compounds are higher than the one of zinc, making the coating more noble [18,19, hindering dissolution of the sacrificial layer and the hydrogen evolution.…”

Section: Discussionmentioning

confidence: 99%

“…On the other hand, the electrochemical potentials of Fe-Zn compounds are higher than the one of zinc, making the coating more noble [18,19, hindering dissolution of the sacrificial layer and the hydrogen evolution. Finally, the continuity of coatings grown at moderate temperature could also be an advantage for the corrosion resistance since Evandro de Azevedo Alvarenga and Vanessa de Freitas Cunha Lins have reported that thermally induced cracking could reduce the barrier protection against corrosion in duplex coatings based on GA coatings, notwithstanding, cracking does not affect the sacrificial and inhibition protections [17].…”

Section: Discussionmentioning

confidence: 99%

“…Duplex coatings combine a sacrificial Zn-rich coating (for instance: HDG, GI or GA) with an organic topcoat, which improves the protection against corrosion. As a matter of fact, the organic coating delays the oxidation of zinc, and the zinc layer captures the oxidizing molecules that diffuse through the polymer [8,16,17]. Since, the lifetime of duplex coatings is highly dependent on the adhesion of the organic layer to the sacrificial layer, sand blasting on batch HDG steel, or conversion treatments on GI sheets, are usually performed before painting to remove zinc oxide and improve the adhesion of the paint.…”

Section: Introductionmentioning

confidence: 99%

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General vapour-phase galvanizing and duplex coatings

Petit

2019

Surface and Coatings Technology

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General vapour-phase galvanizing produces fully alloyed Fe-Zn coatings on steel by exposing complex-shaped articles to hot zinc vapours in vacuum. This way, the processing temperature can be reduced to 350°C. The growth from the gas phase generates microstructures different than other galvanizing technologies. Changing the temperature of growth produces different microstructures in coatings of similar thickness. Mechanical properties are correlated to these microstructures. The chemical properties and the natural roughness of the alloyed surface provide excellent adhesion of the organic topcoat in duplex coatings on vapour-phase galvanized steel. We have performed salt spray and Kesternich tests. The corrosion resistance of bare coatings and duplex coatings are superior to the one of commercial galvanized and galvannealed steels. The specific protocol making general vapour-phase galvanizing possible is presently named as "Epanizing".

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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General vapour-phase galvanizing and duplex coatings

Petit

2019

Surface and Coatings Technology

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“…The zinc oxide also creates a barrier that protects the carbon steel from aggressive environments [8]. Among the galvanizing techniques, the use of zinc electroplating stands out [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Influence of current density and temperature in the zinc electroplating process at sulfate-based acid solution: study on process efficiency and coating morphology

et al. 2021

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Zinc as a metallic coating is a common strategy to protect the carbon steel against corrosion. The most common process of zinc deposition is known as electroplating. Because of the high toxicity of cyanide-based baths, the interest in acid baths has grown, but they present many challenges to be overcome. Several operational parameters and bath constitution – such as current density, pH, and zinc concentration – can impact the current efficiency, deposit quality, and coating morphology. In this work, the process efficiency and the coating morphology were evaluated on electroplated AISI 1008 carbon steel samples. The current density and temperature were individually varied on a range from 7.5 mA.cm-2 to 30.5 mA.cm-2, and from 40 °C to 60 °C, respectively. The process efficiency was evaluated by current efficiency (eC). The surface morphology was analyzed by both optical microscopy (OM) and scanning electron microscopy (SEM). Varying the bath temperature did not promote impacts in the current efficiency, which remained in all temperatures evaluated over 95%. On the other hand, increasing the current density, increased the current efficiency, starting from (85 ± 2)% at 7.5 mA.cm-2 to (92 ± 2)% at 19.0 mA.cm-2, and (95 ± 1)% at 30.5 mA.cm-2. Through OM and SEM analysis, the increase in the temperature tended to turn the coating rougher, and the sample was not completely covered at 7.5 mA.cm-2. Therefore, we recommend the use of a temperature between 40 °C and 50 °C associated with a current density of 30.5 mA.cm-2.

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Anticorrosive performance and corrosion mechanisms of Zn–Mn‐coated steel

Stein

Claudel

Allain-Bonasso

et al. 2022

Materials & Corrosion

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The anticorrosive performance of pulse electrodeposited Zn-Mn deposits was investigated according to the salt spray test DIN EN ISO 9227, commonly used in the automotive industry. A comprehensive analysis of the corrosion products was conducted on the surface and cross-sections via X-ray diffraction and scanning electron microscopy to define the corrosion mechanisms involved. The results revealed a significant enhancement of the anticorrosive performance of Zn-Mn deposits over commercial Zn through a complex corrosion mechanism. The protective coating evolves continuously with exposition time. A preferential dissolution of Mn is observed leading to the formation of a compact layer of zinc hydroxychloride. Moreover, an overlayer of manganese oxide and zinc oxide is highlighted at prolonged exposures due to an increase in interface pH.

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Atmospheric corrosion evaluation of electrogalvanized, hot-dip galvanized and galvannealed interstitial free steels using accelerated field and cyclic tests

Cited by 25 publications

References 36 publications

General vapour-phase galvanizing and duplex coatings

General vapour-phase galvanizing and duplex coatings

Influence of current density and temperature in the zinc electroplating process at sulfate-based acid solution: study on process efficiency and coating morphology

Anticorrosive performance and corrosion mechanisms of Zn–Mn‐coated steel

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