Characteristics of Ni deposition in an alkaline bath for Zn–Ni alloy deposition on steel plates

Lee, Hwa Young; Kim, Sung Gyu

doi:10.1016/s0257-8972(00)00731-3

“…This bath results in a much more uniform deposition surface, but still contains voids and cracks on the surface. Zn-Ni coatings with more compacted spherical grains exhibit better corrosion protection than other morphologies (4).…”

Section: Characterization Of the Electrodeposited Zn-ni Coatingsmentioning

confidence: 94%

“…Originally zinc was alloyed with cadmium, but due to the harsh environmental conditions associated with cadmium, other metals were examined (4,5). Zinc-nickel alloys were examined as a replacement since nickel is cheap, easy to work with and the alloys offer comparable, if not better corrosion resistance than zinc-cadmium alloys (2).…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Deposition of γ-Phase Zinc-Nickel Alloys from Alkaline Solution

Conrad¹,

Corbett²,

Golden³

2011

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Zinc-nickel alloys with 8-15% nickel were deposited onto stainless steel for corrosion protection. Alkaline deposition conditions were utilized given that alkaline systems have been found to offer superior substrate coverage which results in better corrosion protection of the metal substrate (stainless steel) compared to acid bath depositions. This method utilizes ammonium hydroxide as the base source with a working pH range of 9-9.5. Sodium acetate was used as the complexing ligand as it was found to stabilize the metal ions in the electrolytic solution. Strongly adhering, quality deposits were obtained with electrodeposition at room temperature. Bath compositions and applied potential had an effect on morphology of the films as seen in scanning electron microscopy. Upon examination by x-ray diffraction and atomic absorption spectroscopy, all deposits were confirmed as γ phase zinc-nickel alloys with a nickel content of 8-15%. The corrosion potential for the γ-phase coatings was improved over the pure zinc coatings.

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“…Several nickel salt sources were examined as nickel ion sources for deposition. Typically nickel sulfate hexahydrate is used as a nickel source in Zn-Ni alloy depositions carried out in alkaline medium (4). Nickel sulfate hexahydrate readily dissolves in water, providing a source of nickel ions in an aqueous solution.…”

Section: Deposition Bath Compositionmentioning

confidence: 99%

“…The electrodeposition of metallic alloys is of great interest because the mechanical and chemical properties of the metals involved can be increased when alloyed (3). Originally zinc was alloyed with cadmium, but due to the harsh environmental conditions associated with cadmium, other metals were examined (4,5). Zinc-nickel alloys were examined as a replacement since nickel is cheap, easy to work with and the alloys offer comparable, if not better corrosion resistance than zinc-cadmium alloys (2).…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Deposition of γ-Phase Zinc-Nickel Alloys from Alkaline Solution

Conrad

¹

,

Corbett

²

,

Golden

³

2011

J. Electrochem. Soc.

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Zinc-nickel alloys with 8-15% nickel were deposited onto stainless steel for corrosion protection. Alkaline deposition conditions were utilized given that alkaline systems have been found to offer superior substrate coverage which results in better corrosion protection of the metal substrate (stainless steel) compared to acid bath depositions. This method utilizes ammonium hydroxide as the base source with a working pH range of 9-9.5. Sodium acetate was used as the complexing ligand as it was found to stabilize the metal ions in the electrolytic solution. Strongly adhering, quality deposits were obtained with electrodeposition at room temperature. Bath compositions and applied potential had an effect on morphology of the films as seen in scanning electron microscopy. Upon examination by x-ray diffraction and atomic absorption spectroscopy, all deposits were confirmed as γ phase zinc-nickel alloys with a nickel content of 8-15%. The corrosion potential for the γ-phase coatings was improved over the pure zinc coatings.

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“…The interaction enhanced the polarization of nickel at constant current density resulting in anomalous codeposition. Studies on zinc-nickel alloy deposition from alkaline bath [6] revealed that the nickel content in the deposition layer was suppressed at high current density and that the nickel content in the alloy was not affected by the presence of TEA in the alkaline bath. Organic compounds are added to the plating baths to increase polarization even at low current densities [7].…”

Section: Discussionmentioning

confidence: 99%

Zinc-Nickel Alloy Electrodeposition – Influence of Triethanolamine

Ravindran

¹

,

Muralidharan

²

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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Characteristics of Ni deposition in an alkaline bath for Zn–Ni alloy deposition on steel plates

Cited by 50 publications

References 9 publications

Electrochemical Deposition of γ-Phase Zinc-Nickel Alloys from Alkaline Solution

Electrochemical Deposition of γ-Phase Zinc-Nickel Alloys from Alkaline Solution

Electrochemical Deposition of γ-Phase Zinc-Nickel Alloys from Alkaline Solution

Zinc-Nickel Alloy Electrodeposition – Influence of Triethanolamine

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