Structure of Electrodeposited Zn–Mn Alloy Coatings

Tsuchiya, Yasuo; Hashimoto, Satoshi; Ishibashi, Yoïchi; Urakawa, Takayuki; Sagiyama, Masaru

doi:10.2355/isijinternational.40.1024

Cited by 13 publications

(10 citation statements)

References 7 publications

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“…This trend is consistent with high-manganese-content cast Cu-Mn alloys [17][18][19][20] and electrodeposited Zn-Mn. [5] Figure 2 shows the XRD patterns (-2 scan) of asdeposited Cu-Mn alloy coatings (2.1 to 96.1 at. pct Cu) obtained at pH 2.6 to 2.8.…”

Section: Methodsmentioning

confidence: 99%

“…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%

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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: Methodsmentioning

confidence: 99%

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][10][11][12][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.''…”

mentioning

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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“…Iz tabele 2 se može zapaziti porast sadržaja Mn u prevlaci sa porastom gustine struje taloženja. Ova pojava je poznata osobina procesa taloženja Zn−Mn legura, dokazana u praktično svim vrstama elektrolita za taloženje [18,22] i potvrđuje da proces pripada normalnom tipu taloženja legura [23].…”

Section: Morfologija Prevlaka Zn−mn Legura Iz Pirofosfatnog Rastvoraunclassified

The peculiarities of electrochemical deposition and morphology of ZnMn alloy coatings obtained from pyrophosphate electrolyte

Bučko¹,

Stevanović²,

Tomić

et al. 2011

Hem Ind

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The first successful attempt to electrodeposit ZnMn alloy coatings from alkaline bath was made only a few years ago. In this kind of solution, potassium pyrophosphate (K4P2O7) serves both as a complexing agent and as the basic electrolyte. The aim of this work was to study the electrodeposition process and properties of ZnMn alloy coatings deposited from pyrophosphate solution, with a new kind of alkaline pyrophosphate bath. Namely, chloride salts were used as the source of metal ions and ascorbic acid was used as reducing agent. The composition of the plating solution was as follows: 1 mol dm-3 K4P2O7 + 0.017 mol dm-3 ascorbic acid + 0.05 mol dm-3 ZnCl2 + 0.05 mol dm-3 MnCl2•4H2O. Cathodic processes during the alloy electrodeposition were investigated using linear voltammetry. The influence of addition of small amounts of ascorbic acid on the cathodic processes was established. It was shown that this substance inhibits hydrogen evolution and increases the current efficiency of alloy deposition. The current efficiency in the plating bath examined was in the range of 25 and 30%, which was quite higher as compared to the results reported in the literature for electrodeposition of ZnMn alloy from pyrophosphate bath. Electrodeposition of ZnMn alloys was performed galvanostatically on steel panels, at current densities of 20120 mA cm-2. The coatings with the best appearance were obtained at current densities between 30 and 80 mA cm-2. The surface morphology studies, based on atomic force microscopy measurements, showed that morphology of the deposits is highly influenced by deposition current density. ZnMn coating deposited at 30 mA cm-2 was more compact and possessed more homogeneous structure (more uniform agglomeration size) than the coating deposited at 80 mA cm-2. Such dependence of morphology on the current density could be explained by the high rate of hydrogen evolution reaction during the electrodeposition process

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Structure of Electrodeposited Zn–Mn Alloy Coatings

Cited by 13 publications

References 7 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

The peculiarities of electrochemical deposition and morphology of ZnMn alloy coatings obtained from pyrophosphate electrolyte

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