Characteristics of tungsten coatings deposited by molten salt electro-deposition and thermal fatigue properties of electrodeposited tungsten coatings

Qi, Yanfei; Tang, Yunhui; Wang, Bo; Zhang, Ming; Ren, Xiqiang; Li, Yungang; Ma, Yutian

doi:10.1016/j.ijrmhm.2019.03.006

Cited by 14 publications

(9 citation statements)

References 23 publications

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“…Thus, the electrodeposition of flat and dense tungsten coatings is worth investigating. Numerous studies have reported the electrodeposition of tungsten from the high-temperature molten salts, such as fluorides, 1,2 chlorides, [2][3][4] fluoride-chloride mixtures [2][3][4][5][6][7][8] and oxides. 2,3,9 It is known that dense and coherent tungsten deposits are more easily obtained from molten fluorides than from molten chlorides.…”

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confidence: 99%

Electrodeposition of Tungsten from Molten KF–KCl–WO₃ and CsF–CsCl–WO₃

Ide

Meng

Norikawa

et al. 2021

J. Electrochem. Soc.

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The electrodeposition of W films was investigated in KF-KCl eutectic melts after adding 0.5-2.0 mol% of WO6 at 923 K. Cyclic voltammetry at a Ag electrode suggested that the electrodeposition of W from W(VI) ions proceeds from 1.65 V vs. K + /K. Electrodeposition of α-W was confirmed by XRD analysis. The effect of current density and added amount of WO3 on the morphology of W films was investigated by surface and crosssectional SEM, which indicated that the best W film having thickness of ca. 15 μm was obtained at 12.5 mA cm −2 and 2.0 mol% of WO3. Although the film thickness was increased to ca. 30 μm by increasing the charge density, the surface roughness was significantly increased. To suppress the growth of crystal grains, electrodeposition of W was also investigated in CsF-CsCl eutectic melts at lower temperature of 873 K. The XRD confirmed the existences of both α-W and β-W in the W films. The SEM observations revealed that dense and smooth W films having thickness of ca. 30 μm was successfully obtained.

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confidence: 99%

Electrodeposition of Tungsten from Molten KF–KCl–WO₃ and CsF–CsCl–WO₃

Ide

Meng

Norikawa

et al. 2021

J. Electrochem. Soc.

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“…Figure a shows a schematic of the electrodeposition of W in molten KF–KCl–WO 3 . We have previously confirmed that WO 3 was dissolved as WO 3 F 3 3– in KF–KCl . At the cathode, W was deposited from WO 3 F 3 3– . WO 3 normalF 3 3 − + 6 normale − → normalW ( s ) + 3 normalO 2 − + 3 normalF − At the carbon anode, O 2 , CO 2 , and/or CO gases were produced. 2 normalO 2 − → normalO 2 ( g ) + 4 normale − 2 normalO 2 − + normalC → CO 2 ( g ) + 4 normale − normalO 2 − + normalC → CO ( g ) + 2 normale − …”

Section: Electrodeposition Of Tungstenmentioning

confidence: 69%

“…We have previously confirmed that WO 3 was dissolved as WO 3 F 3 3− in KF−KCl. 48 At the cathode, W was deposited from WO 3 F 3…”

Section: Molten Kf−kcl Systemmentioning

confidence: 99%

“…We have previously confirmed that WO 3 was dissolved as WO 3 F 3 3− in KF−KCl. 48 At the cathode, W was deposited from WO 3 F 3 From the cyclic voltammogram in KF−KCl−WO 3 shown in Figure 6b, the cathodic current due to W deposition is observed at approximately 1.6 V vs K + /K. Galvanostatic electrolysis was then conducted at the Cu electrode.…”

Section: Molten Kf−kcl Systemmentioning

confidence: 99%

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A New Concept of Molten Salt Systems for the Electrodeposition of Si, Ti, and W

Norikawa

2023

Acc. Chem. Res.

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Conspectus This Account describes the results of the electrodeposition of film-like Si, Ti, and W by utilizing molten salts selected based on a new concept. The proposed molten salt systems, KF–KCl and CsF–CsCl, have high fluoride ion concentrations, relatively low operating temperatures, and high solubility in water. First, KF–KCl molten salt was used for the electrodeposition of crystalline Si films to establish a new fabrication method for Si solar cell substrates. The electrodeposition of Si films from the molten salt at 923 and 1023 K was successfully achieved using K2SiF6 or SiCl4 as the Si ion source. The crystal grain size of Si was larger at higher temperatures, indicating that higher temperatures are advantageous for the application of Si solar cell substrates. The resulting Si films underwent photoelectrochemical reactions. Second, the electrodeposition of Ti films using the KF–KCl molten salt was investigated to easily impart the properties of Ti, such as high corrosion resistance and biocompatibility, to various substrates. Ti films with a smooth surface were obtained from the molten salt containing Ti(III) ions at 923 K. Electrochemical tests in artificial seawater revealed that the electrodeposited Ti films had no voids and cracks and that the obtained Ti-coated Ni plate had a high corrosion resistance against seawater. Finally, the molten salts were used for the electrodeposition of W films, which are expected to be used as diverter materials for nuclear fusion. Although the electrodeposition of W films was successful in the KF–KCl–WO3 molten salt at 923 K, the surface of the films was rough. Therefore, we used the CsF–CsCl–WO3 molten salt, which can be employed at lower temperatures than KF–KCl–WO3. We then successfully electrodeposited W films with a mirror-like surface at 773 K. Such a mirror-like metal film deposition has not been reported before using high-temperature molten salts. Further, the temperature dependence of the crystal phase of W was revealed by the electrodeposition of W films at 773–923 K. β-W was obtained at 773 and 823 K, α-W was obtained at 923 K, and a mixed phase of α- and β-W was obtained at 873 K. In addition, single-phase β-W films with a thickness of approximately 30 μm were electrodeposited, which has not been reported before. The results show that our proposed molten salt systems are advantageous for electroplating Si, Ti, and W. Our approach is also expected to be applicable for the electrodeposition of other metals such as Zr, Nb, Mo, Hf, and Ta.

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“…1–3 The Na 2 WO 4 –WO 3 molten salt system is predominantly utilized for tungsten coating since WO 3 is stable and relatively easy to prepare. 4–6 Electrodeposition of tungsten with molten salts as a medium is an effective approach in the production of tungsten coatings 7–12 and has garnered considerable attention. 13–18 In terms of electrode selection, studies have suggested that copper electrodes in Na 2 WO 4 –WO 3 molten salt can produce dense tungsten coatings.…”

Section: Introductionmentioning

confidence: 99%

Effect of electric fields on tungsten distribution in Na₂WO₄–WO₃ molten salt

Guo,

Sun,

Jiao

et al. 2024

Phys. Chem. Chem. Phys.

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Characteristics of tungsten coatings deposited by molten salt electro-deposition and thermal fatigue properties of electrodeposited tungsten coatings

Cited by 14 publications

References 23 publications

Electrodeposition of Tungsten from Molten KF–KCl–WO₃ and CsF–CsCl–WO₃

Electrodeposition of Tungsten from Molten KF–KCl–WO₃ and CsF–CsCl–WO₃

A New Concept of Molten Salt Systems for the Electrodeposition of Si, Ti, and W

Effect of electric fields on tungsten distribution in Na₂WO₄–WO₃ molten salt

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Characteristics of tungsten coatings deposited by molten salt electro-deposition and thermal fatigue properties of electrodeposited tungsten coatings

Cited by 14 publications

References 23 publications

Electrodeposition of Tungsten from Molten KF–KCl–WO3 and CsF–CsCl–WO3

Electrodeposition of Tungsten from Molten KF–KCl–WO3 and CsF–CsCl–WO3

A New Concept of Molten Salt Systems for the Electrodeposition of Si, Ti, and W

Effect of electric fields on tungsten distribution in Na2WO4–WO3 molten salt

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Product

Resources

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Electrodeposition of Tungsten from Molten KF–KCl–WO₃ and CsF–CsCl–WO₃

Electrodeposition of Tungsten from Molten KF–KCl–WO₃ and CsF–CsCl–WO₃

Effect of electric fields on tungsten distribution in Na₂WO₄–WO₃ molten salt