Morphology and Composition of Electrodeposited CoMn Layers

Nikolova, M; Atanassov, N.; Fischer‐Bühner, Jörg; Zielonka, A.

doi:10.1080/00202967.2000.11871328

Cited by 9 publications

(8 citation statements)

References 11 publications

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“…Pure Mn coatings on steel, however, are highly reactive and exhibit a high corrosion current and quick dissolution. [1,2] Alloying of Mn with other metals such as zinc, [3][4][5][6][7][8] nickel, [9,10] iron, [11,12] chromium, [13] cobalt, [14] or tin [15] potentially enables tailoring of the corrosion potential and dissolution kinetics, improving the coating performance. Ideal sacrificial coatings should provide, in addition, suitable contact and soldering surfaces for any foreseeable application in the field and, therefore, should exhibit a low friction coefficient, low ductility, good electrical conductivity, and good solderability both at the nano-and microscale, where surface interactions will occur.…”

Section: Introductionmentioning

confidence: 99%

Electrodeposition and characterization of sacrificial copper-manganese alloy coatings: Part II. Structural, mechanical, and corrosion-resistance properties

Gong

Wei

Barnard

et al. 2005

Metall Mater Trans A

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The structure and properties of electrodeposited Mn-rich Cu-Mn coatings were studied in order to assess their potential to provide sacrificial galvanic protection to steels. It is found that a small amount of codeposited copper can stabilize the ductile as-deposited centered tetragonal ␥Ј phase against roomtemperature recrystallization to the stable bcc ␣ phase. The time to transformation is increasingly delayed with increasing copper content. Phase transformation of crystalline films does not follow the Johnson-Mehl-Avrami-Kolmogorov equation for nucleation and growth transformation. Amorphous coatings do not show any structural transformation at room temperature. Nanomechanical and tribological measurements showed that Cu-Mn coatings have a lower friction coefficient than reference Cd coatings. Cu codeposition reduces the coating's hardness and elastic modulus and increases the resistance to plastic penetration with respect to pure Mn. Cu-Mn coatings show a barrier or passive behavior under anodic polarization, while the sacrificial characteristics are still preserved. The corrosion appears uniform, and the formation of MnO 2 and Cu 2 O upon anodic polarization may account for the good corrosion performance of the coatings.

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Section: Introductionmentioning

confidence: 99%

Electrodeposition and characterization of sacrificial copper-manganese alloy coatings: Part II. Structural, mechanical, and corrosion-resistance properties

Gong

Wei

Barnard

et al. 2005

Metall Mater Trans A

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“…5 Pure manganese is not usually considered a suitable protective coating for steel because of its high chemical reactivity, which leads to fast dissolution of the coating, and its brittle nature. [5][6][7][8] The first problem, however, can be overcome by alloying Mn with other metals such as zinc, 6,9-13 nickel, 14,15 iron, 16,17 chromium, 18 cobalt, 19 or tin. 20 Among these, electrodeposited Zn-Mn alloys are claimed to approach ''real commercial exploitation.''…”

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confidence: 99%

Electrodeposition and Characterization of Sacrificial Copper-Manganese Alloy Coatings

Gong

Zangari

2004

J. Electrochem. Soc.

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Cu-Mn electrodeposition from simple sulfate electrolytes with the only addition of ammonium sulfate was studied under different current densities, at pH 2.6-2.8 and pH 6.4-6.6, and at different cupric ion concentrations. An electrochemical investigation of this Cu-Mn electrodeposition system was conducted by potentiodynamic methods and cyclic voltammetry. Electrodeposition was performed galvanostatically. Mn content in the alloy increased with increasing current density. Three types of coatings were obtained: spongy Cu-rich oxygen-containing films at low current density, crystalline Mn-rich coatings at intermediate current density ͑type I͒, and amorphous coatings at high current density ͑type II͒. At high pH ͑6.4-6.6͒, the composition of type I coatings could be controlled by adjusting the current density, while at low pH ͑2.6-2.8͒ composition becomes more controllable by varying the Cu 2ϩ concentration (͓Cu 2ϩ ͔). The optimal current density to obtain type I coatings is shifted upward with increasing ͓Cu 2ϩ ͔. A Cu-rich interlayer is formed between the Cu-Mn film and the stainless steel substrate. The bulk of type II coatings is mainly composed of metallic Cu and Mn. Metal complexation equilibria with NH 3 can explain the influence of Cu additions on coating morphology and composition.Electroplated cadmium ͑Cd͒ is widely utilized in surface finishing applications to improve corrosion resistance and tribological properties of a variety of components. In these instances, cadmium coatings provide sacrificial corrosion protection, low friction coefficient, ductility, good electrical conductivity, and solderability. However, both cadmium as a metal and cadmium processing, which utilizes cyanide-based solutions, are extremely toxic to the environment and to humans, and the release of the metal and of processing effluents is strictly controlled. Until now, no single coating has been proposed that possesses all the attributes needed to replace cadmium. 1-4 It is thus important to develop alternative, environmentally friendly processes and materials capable of substituting Cd as a sacrificial coating to steel.Electrodeposited coatings of manganese ͑Mn͒ and its alloys potentially combine high corrosion protection performance, good tribological behavior, and suitable mechanical properties. Therefore, they have been studied as a replacement for cadmium in the sacrificial protection of steel. 5 Pure manganese is not usually considered a suitable protective coating for steel because of its high chemical reactivity, which leads to fast dissolution of the coating, and its brittle nature. 5-8 The first problem, however, can be overcome by alloying Mn with other metals such as zinc, 6,9-13 nickel, 14,15 iron, 16,17 chromium, 18 cobalt, 19 or tin. 20 Among these, electrodeposited Zn-Mn alloys are claimed to approach ''real commercial exploitation.'' 21 Mn and Zn in these alloys show synergistic effects with a corrosion resistance superior to the individual metals and to other Zn alloys in laboratory chloride environments. 11 Thi...

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“…This periodic hydrogen evolution thus, indeed, can be related to the formation of the layered structure as was also considered in previous works. [1][2][3][4][5][6] It was also reported 3 that the cell current amplitude exhibits an apparently periodic variation as the deposition proceeds and the amplitude variations amount to a few percent of the average current value. These current variations are definitely in close relationship with the formation of the layered structure.…”

mentioning

confidence: 88%

“…It was revealed in earlier works [1][2][3] that during the potentiostatic electrodeposition from sulfamate baths containing a low concentration of Co 2+ and Mn 2+ ions (less than 0.1 M) and boric acid, a nonconventional, dendrite-like deposit growth occurs at large negative overpotentials. An overall chemical analysis of the deposits revealed the presence of Co, Mn, O, B and H (with the following typical ranges of concentration: Co: 28-35 at.%; Mn: 3.8-6.2 at.%; O: 45-55 at.%; B: 8.2-14 at.% and H: 5.4-9.5 at.% 4 ).…”

mentioning

confidence: 99%

“…An overall chemical analysis of the deposits revealed the presence of Co, Mn, O, B and H (with the following typical ranges of concentration: Co: 28-35 at.%; Mn: 3.8-6.2 at.%; O: 45-55 at.%; B: 8.2-14 at.% and H: 5.4-9.5 at.% 4 ). The analysis of cyclic voltammetry curves of the electrodeposition bath led to the conclusion [1][2][3][4][5] that the incorporation of the other elements besides Co into the deposit is the result of a new, complex interaction between the specific bath components that arises at the highly negative potentials applied during deposition.…”

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confidence: 99%

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Compositional, Structural and Magnetic Study of Layered Co-Mn-O-B Deposits Formed during Potentiostatic Electrodeposition Exhibiting Current Oscillations

Rashkov

Zsurzsa

Jóni

et al. 2017

J. Electrochem. Soc.

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It was reported previously [Trans. Inst. Met. Finish. 85, 94 (2007)] that during potentiostatic electrodeposition from electrolytes containing a low concentration of Co 2+ and Mn 2+ ions and boric acid, a layered structure consisting of alternating Co-rich and Mn-O-B-rich zones can be formed. In the present study, electrodeposition was carried out from both sulfamate and sulfate electrolytes. A cyclic voltammetry study was performed for identifying the potential intervals associated with the deposition regimes of the components. The current amplitude data recorded during electrodeposition exhibited a periodic oscillation with a period of 1.9 ± 0.1 s. The fast Fourier transforms of the chronoamperometric data showed two maxima, the ∼0.5 Hz peak corresponding to the major oscillation period and the ∼1 Hz peak to the first harmonic one. An analysis of the overall deposit composition revealed that the Mn/Co ratio was typically in the range from about 0.05 to 0.25, the sulfamate bath resulting in systematically higher values. The X-ray diffraction patterns of the deposits were dominated by a broad Gaussian peak characteristic of an amorphous phase. The room-temperature magnetization indicated that the deposits contain nanometer-sized magnetic entities with superparamagnetic behavior.

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Morphology and Composition of Electrodeposited CoMn Layers

Cited by 9 publications

References 11 publications

Electrodeposition and characterization of sacrificial copper-manganese alloy coatings: Part II. Structural, mechanical, and corrosion-resistance properties

Electrodeposition and characterization of sacrificial copper-manganese alloy coatings: Part II. Structural, mechanical, and corrosion-resistance properties

Electrodeposition and Characterization of Sacrificial Copper-Manganese Alloy Coatings

Compositional, Structural and Magnetic Study of Layered Co-Mn-O-B Deposits Formed during Potentiostatic Electrodeposition Exhibiting Current Oscillations

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