Corrosion resistance of electroplated zinc alloy coatings

Short, N. R.; Abibsi, A.; Dennis, J.K.

doi:10.1080/00202967.1989.11870845

Cited by 96 publications

(33 citation statements)

References 12 publications

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“…This hydroxide further converts to Zn 5 (OH) 8 Cl 3 , which is again reported to be a rather stable compound [3,20]. It is found in the results that pure Zn and Zn-Co-Fe alloys with low alloying elements can protect the steel substrate for a rather short period but the range of protection during that time is higher than that for the Zn-CoFe-3 alloy.…”

Section: Resultsmentioning

confidence: 61%

“…Electroplated zinc (Zn) and zinc-cobalt (Zn-Co) alloys are used as corrosion protective coatings especially in aerospace and automotive industries [1][2][3][4][5]. Electrodeposited Zn-Co-Fe alloys are a recent addition to the family of Zn-based alloys.…”

Section: Introductionmentioning

confidence: 99%

“…Electrodeposited Zn-Co-Fe alloys are a recent addition to the family of Zn-based alloys. In case of Zn-Co alloys, the information is limited to a small range of Co concentrations (0-2 wt%) and little information is available in the literature on Zn-Co-Fe alloys [2][3][4]. Electrodeposited Zn-Co alloy coatings can provide a good balance between barrier and sacrificial properties in a sense that they are more efficient barrier coatings than pure zinc while still providing some sacrificial protection to steel.…”

Section: Introductionmentioning

confidence: 99%

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SVET study of the corrosion protection of electrodeposited Zn and Zn‐Co‐Fe alloy coated steels

Lodhi

Zhan

Mol

et al. 2008

Materials & Corrosion

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The scanning vibrating electrode technique (SVET) was applied to study the corrosion resistance of partially coated (Zn and various Zn-Co-Fe alloys) and partially exposed steel samples in 10 mM NaCl solution. The sacrificial properties and the protection range decreases with increase in Co content in the alloy. For high Co content in the alloy, the coating becomes more noble to steel and loses its sacrificial protection. The barrier resistance of the coatings increases with the increase in Co content in the alloy coating. ZnCo-Fe alloys with high Co content (i.e., 32 wt% Co and 1 wt% Fe) showed excellent barrier properties due to passivation after dezincification protecting the underlying steel. An intermediate region of compositions can be distinguished in which the coatings provide a good combination of sacrificial and barrier resistance properties and also a reasonable protection range.

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Section: Resultsmentioning

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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SVET study of the corrosion protection of electrodeposited Zn and Zn‐Co‐Fe alloy coated steels

Lodhi

Zhan

Mol

et al. 2008

Materials & Corrosion

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“…Most results reported on the electrodeposition of Zn-Co alloy coatings showed that the maximum amount of cobalt * e-mail: ikarahan@mku.edu.tr in their deposits was about 6-7 wt.% [12,13]. The deposits of Zn-Co alloys with cobalt content of more than 6 or 7 wt.% have not been widely reported [14,15]. Fei et al [16] have obtained Zn-Co alloy deposits in the wide cobalt content range of 10-90%.…”

Section: Introductionmentioning

confidence: 99%

Effect of Borax Pentahydrate Addition to Acid Bath on the Microstructure and Corrosion Resistance of Zn-Co Coating

Karahan

2015

Acta Phys. Pol. A

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In this work, the Zn-Co coatings were synthesized on AISI 4140 steel and aluminum plates by using potentiostatic electrodeposition technique in sulphate-based acidic baths with 0, 20, 40 and 60 g l −1 of borax pentahydrate, as additive. The effect of borax pentahydrate on the microstructure of the samples was observed using scanning electron microscopy and X-ray diffractometer. The deposition process was investigated by cyclic voltammetry. The effect of borax pentahydrate on the corrosion resistance of the samples was studied by potentiodynamic polarization technique. The results have demonstrated, that the addition of borax pentahydrate was in favor of the growth of grains. The morphology of pyramidal islands on the surface was changed to a more flat structure. The results have also demonstrated that the effect of borax pentahydrate was not monotonous. With increasing concentration, the corrosion potential was at minimum and the charge transfer resistance Rt was at maximum for the sample obtained from the bath with 60 g l −1 of borax pentahydate, indicating that this sample showed the best corrosion resistance. It was found that current density first decreased and than increased, due to adsorption of a complex of borax pentahydrate and/or changes in the morphology, however, the initial deposition potential was not affected. The addition of borax pentahydrate to the bath led to formation of the best Zn-Co deposits, composed of coalesced globular fine grains, smaller than ≈2 µm in diameter. In addition, all of the studied Zn-Co deposits consisted of η phases. It is suggested that Zn-Co deposits produced in the bath containing 60 g l −1 of borax pentahydrate probably offer sacrificial protection to the steel substrate.

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“…The zinc-nickel alloy deposit has 90 -95% zinc [1] and the deposition is anomalous, i.e., the less noble metal, zinc, deposits preferentially. There are broadly two types of plating baths for Zn-Ni alloy, namely the acid type and the alkaline type [2,3].…”

Section: Introductionmentioning

confidence: 99%

Zinc-Nickel Alloy Electrodeposition – Influence of Triethanolamine

Ravindran

Muralidharan

2007

Port. Electrochim. Acta

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Compared to pure zinc plating, zinc alloys provide several advantages. A zinc alloy generally offers superior sacrificial protection to steel since it corrodes more slowly than pure zinc. A search for a non-cyanide zinc plating bath resulted on the development of a zinc nickel sulphamate bath. To obtain better quality zinc-nickel deposits, triethanolamine was added to the bath. In this paper the influence of triethanolamine in zinc-nickel plating from sulphamate bath has been investigated through current efficiency measurements, cyclic voltammetry, scanning electron microscope, and X-ray diffraction techniques. In the presence of triethanolamine in the zinc-nickel sulphamate bath the current efficiency of alloy deposition increased to a maximum of 99% at the current density of 1.5 Adm -2 and thereafter decreased. TEA adsorbed on the electrode surface obeying Henry's isotherm. On mild steel surfaces, uniform smooth slate gray deposit with smaller crystallites was produced, in presence of TEA in solution, and the electrodeposits exhibited additional Zn(OH) 2 and γ-Ni 3 Zn 22 phases. Hydrogen evolution was suppressed by TEA and thereby current efficiency is increased for alloy deposition.Keywords: cyclic voltammetry, electrodeposition, triethanolamine, XRD, Zn-Ni. IntroductionPrecoated electrogalvanised Zn-Ni sheet has offered the automotive and computer industries a superior prefabricated stock resulting in much-improved corrosion resistance. The zinc-nickel alloy deposit has 90 -95% zinc [1] and the deposition is anomalous, i.e., the less noble metal, zinc, deposits preferentially. There are broadly two types of plating baths for Zn-Ni alloy, namely the acid type and the alkaline type [2,3]. The acid bath consists of a mixture of zinc and nickel salts, electrolytes, buffers and optional brighteners. In the alkaline type,

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Corrosion resistance of electroplated zinc alloy coatings

Cited by 96 publications

References 12 publications

SVET study of the corrosion protection of electrodeposited Zn and Zn‐Co‐Fe alloy coated steels

SVET study of the corrosion protection of electrodeposited Zn and Zn‐Co‐Fe alloy coated steels

Effect of Borax Pentahydrate Addition to Acid Bath on the Microstructure and Corrosion Resistance of Zn-Co Coating

Zinc-Nickel Alloy Electrodeposition – Influence of Triethanolamine

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