Influence of Co2+ and Cu2+ on the phase composition of Zn–Ni alloy

Petrauskas, А. V.; Grincevičienė, L.; Češūnienė, A.; Juškėnas, Remigijus

doi:10.1016/j.electacta.2006.01.064

Cited by 8 publications

(9 citation statements)

References 19 publications

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“…Whereas, the height of the two other peaks decreased (Table 3), particularly remarkable for the Zn-Ni/3 mM TEA sample, giving rise to a lower content of the respective phases. It suggests also that these organic compounds changes the codeposition of Zn-Ni, and also that such changes could affect the corrosion resistance of the alloy (Petrauskas et al, 2006). In fact, the data presented in Table 2 shows that the quan-tity of Ni in the coating systems of Zn-Ni alloy and Zn-Ni/3 mM TEA is the same, however the oxidation of the -phase (Peak 2-d) decreases.…”

Section: Polarisation Measurementsmentioning

confidence: 94%

Effect of diethanolamine and triethanolamine on the properties of electroplated Zn–Ni alloy coatings from acid bath

Hammami

Dhouibi²,

Berçot

et al. 2012

Can J Chem Eng

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Section: Polarisation Measurementsmentioning

confidence: 94%

Effect of diethanolamine and triethanolamine on the properties of electroplated Zn–Ni alloy coatings from acid bath

Hammami

Dhouibi²,

Berçot

et al. 2012

Can J Chem Eng

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“…The composition of the nickel and zinc plating solutions were 5 mM NiCl 2 ·6H 2 O, 10 mM ZnCl 2 ·2H 2 O, and 1.0 M NH 4 Cl. The concentrated ammonia solution was added dropwise to the solutions to obtain a pH of 5.8.…”

Section: Methodsmentioning

confidence: 99%

Electrocodeposition of Nanocrystalline Single-Phase γ-Zn[sub 3]Ni Alloy on Composite Graphite

M.A.Tehrani

Ghani

2008

J. Electrochem. Soc.

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The single-phase gamma zinc-nickel alloy ͑␥-Zn 3 Ni͒ nanocrystal was deposited on composite graphite electrode at a scan rate of 10,000 mV s −1 . The average particle size obtained was 11.8 Ϯ 3.1 nm. Transmission electron microscopy analysis indicated that codeposition applied potential, i.e., nucleation overpotential, scan rate, and codeposition time were critical on crystal sizing and Ni content in the matrix. Cyclic voltammetry and analysis of X-ray diffraction have also indicated that single-phase ͑␥-phase͒ alloy was, indeed, obtained at the scan rate used. The results also revealed that 19.0 wt % Ni nanoparticles were uniformly dispersed in the phase compositions of the alloy coating.Nanostructure materials with their unique and fascinating properties have prompted scientists to explore the possibilities of using them in industrial applications. For example, bimetallic thin films and nanoalloys, especially those with magnetic quality, could be used in storage systems, 1 superconductors, electrochromic materials, catalysts, and decorative and protective coatings. 2,3 Zinc is usually used as sacrificial anode, which provides cathodic protection to iron. However, this coating corrodes rapidly; hence, Zn-Ni alloy coating containing up to 12 wt % Ni 4 is used as the passivation agent to minimize this problem. Zn-Ni alloys exhibit a high protective function against corrosion, good mechanical properties, 5 and low hydrogen brittleness 6 as compared to pure zinc and galvanized steel. It has been widely applied as a highly corrosion-resistant coating, especially in steel mills and automotive and computer industries. 7-9 Zn-Ni alloy has a higher negative potential than cadmium and, hence, dissolves rapidly in corrosive environments. But, it is a good replacement for cadmium coating due to the latter's toxicity. 10 The electrodeposition of Zn-Ni alloy is classified as an anomalous type of codeposition. 11 In the electrodeposition, Zn, a thermodynamically less-noble metal than Ni, is preferentially deposited. The formal electrode potentials ͑E o ͒ for Zn 2+ /Zn and Ni 2+ /Ni pairs are −0.762 and −0.236 V, respectively. The alloy composition always has a greater abundance of zinc than of nickel. Higher Ni content leads to a more-positive open-circuit potential, which in turn reduces the motivation force for the galvanic corrosion. 10 The commonly employed Zn-Ni alloy in the aeronautical industry has 15-22 wt %. 12 Attempts to rationalize the anomalous electrodeposition of the Zn-Ni alloy are not quite successful. 13-15 One reason could be the favorable kinetic effect of Zn deposition as compared to Ni deposition. 13 The increase in pH near the cathode surface, followed by the formation of Zn hydroxide precipitate and the inhibition of Ni discharge, is also suggested. 14,15 In addition to this, the effects of organic additives on improved Ni content in the alloy composition are also investigated. 6,13 There are three intermetallic phases, i.e., ␥, , and ␦ based on Ni content, on the equilibrium-phase diagram for the Zn-Ni...

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“…The corrosion resistance of Zn-Co alloy depends practically on the wt% Co in the deposit, and consequently, its phase structure depending on c.d. employed for its deposition [18][19][20][21][22][23]. Hence, an effective modulation in composition can be achieved by successive layering of alloys having distinct phase difference, by proper selection of CCCD's.…”

Section: X-ray Diffraction Studymentioning

confidence: 99%

Electrodeposition of Cyclic Multilayer Zn-Co Films Using Square Current Pulses and Investigaions on Their Corrosion Behaviors

Bhat¹,

Hegde²

2012

JMMCE

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The cyclic multilayer alloy (CMA) coatings of Zn-Co have been developed galvanostatically on mild steel (MS), using single bath technique. Depositions were carried out using square current pulses. Corrosion behaviors of the coatings were evaluated by potentiodynamic polarization and electrochemical impedance method, supported by dielectric spectroscopy. The cyclic cathode current densities (CCCD's) and number of layers were optimized for highest corrosion stability of the coatings. The CMA coating developed at 3.0/5.0 A/dm 2 , having 300 layers, represented as (Zn-Co) 3.0/5.0/300 was found to exhibit ~40 times better corrosion resistance compared to monolayer coating, developed from same bath for same time. Substantial improvement in the corrosion resistance of CMA coatings is attributed to layered coating, having alternatively different phase structures, evidenced by XRD study. The formation of multilayer and corrosion mechanism was analyzed using Scanning Electron Microscopy.

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Influence of Co2+ and Cu2+ on the phase composition of Zn–Ni alloy

Cited by 8 publications

References 19 publications

Effect of diethanolamine and triethanolamine on the properties of electroplated Zn–Ni alloy coatings from acid bath

Effect of diethanolamine and triethanolamine on the properties of electroplated Zn–Ni alloy coatings from acid bath

Electrocodeposition of Nanocrystalline Single-Phase γ-Zn[sub 3]Ni Alloy on Composite Graphite

Electrodeposition of Cyclic Multilayer Zn-Co Films Using Square Current Pulses and Investigaions on Their Corrosion Behaviors

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