The effect of electrodeposition conditions and post-annealing on nanostructure of Co–W coatings

Цынцару, Н.; Cesiulis, H.; Budreika, A.; Ye, X.; Juškėnas, Remigijus; Célis, Jean-Pierre

doi:10.1016/j.surfcoat.2012.04.036

Cited by 64 publications

(30 citation statements)

References 37 publications

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“…This opens the window for alternative, durable, cost-effective materials that would be suitable for replacement of noble metals. Among various alternatives, W(Mo)-based alloys with iron group metals, namely Ni, Co and Fe, have attracted considerable research attention during the last decades because of their high electrocatalytic activity [9e11], superior mechanical [12,13], tribological [14e16], anti-corrosion properties [15] and thermal resistance [18,19]. W(Mo) alloy electrodes with iron group metals have been prepared by various methods, such as magnetron sputtering [10,20,21], hydrothermal treatment [22], arc melting [23], mechanical alloying [24e27] and electrodeposition [28e30].…”

Section: Introductionmentioning

confidence: 99%

Electrodeposited tungsten-rich Ni-W, Co-W and Fe-W cathodes for efficient hydrogen evolution in alkaline medium

Vernickaite

Цынцару

Sobczak

et al. 2019

Electrochimica Acta

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The search of active, stable and cost-effective non-noble electrocatalysts for hydrogen evolution reaction (HER) is essential for sustainable energy systems. In this study, the electrodeposited Ni-W, CoW and FeW coatings having 5e30 at.% of W were examined as an alternative electrocatalysts for hydrogen evolution. The electrocatalytic efficiency of the electrodes was investigated on the basis of electrochemical data obtained from steady-state polarization technique in 30 wt% NaOH solution. It was found that with increasing of tungsten content in the deposits up to ~30 at.% a crystal-to-ultra-nanocrystalline transition takes place and the crystal grain size decreases up to 2e4 nm. The high content of W leads to course-grained coatings. These morphological and structural changes showed remarkable impact on the catalytic activity. The maximum catalytic performance was obtained for ultra-nanocrystalline W coatings. Among them the Ni-29at.%W demonstrated the highest apparent exchange current density (ECD) at the room temperature, i.e. 0.55 mA cm À2 , thus indicating more favorable hydrogen reduction. A significant improvement of catalytic activity of all tested cathodes with increasing the temperature of NaOH solution was noticed. Among investigated Co-33at.%W, Fe-30at.%W and Ni-29at.%W cathodes, the last one showed the best performance towards HER (ECD ¼ 14.5 mA cm À2 at 65 C).

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Section: Introductionmentioning

confidence: 99%

Electrodeposited tungsten-rich Ni-W, Co-W and Fe-W cathodes for efficient hydrogen evolution in alkaline medium

Vernickaite

Цынцару

Sobczak

et al. 2019

Electrochimica Acta

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“…Amorphous and crystalline Fe-W, Ni-W and Co-W electrodeposits have been reported in the literature [6][7][8]. XRD analysis results indicated that as-deposited Ni-W alloys having tungsten content in their composition higher than 19-23 at.% forms nanocrystalline ("amorphous-like") structure [9][10][11][12].…”

Section: Introductionmentioning

confidence: 91%

Evaluation of Corrosion and Tribological Behavior of Electrodeposited Tungsten Alloys

Vernickaite

Cesiulis

Цынцару

2017

Proccedings of International Scientific Conference "BALTTRIB 2017"

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Tungsten alloy coatings with iron group metals (Ni, Fe, Co) are considered as advanced materials for various surface engineering applications. Such coatings should be resistant to mechanical and corrosive damage, and to have improved functionality and durability. Accordingly, the objectives of this review consist in a comparative study of available literature on corrosive and wear behavior of electrodeposited tungsten alloys with iron group metals, including our recent results on evaluation of electrodeposited Co-W coatings. The wear and corrosion resistance of Ni-W, Fe-W and Co-W strongly depends on the chosen deposition conditions and subsequently on tungsten content and structure of obtained protective coatings.

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“…%. Coating enrichment by molybdenum with increasing current density is entirely predictable since the molybdate electrochemical behavior is associated with multi-stage process following by chemical reducing of intermediate molybdenum oxides with hydrogen adatoms H ad [27,29,35]. The cathode potential at Co▬Mo▬Zr electrodeposition is rather negative À(2.0-2.8) V (Figure 7b) and it becomes more negative with current density, that resulting in acceleration of side reaction producing H ad which are involved in a chemical step of reducing intermediate molybdenum oxides.…”

Section: Co▬mo▬zr Electrolytic Alloysmentioning

confidence: 99%

Composition Electrolytic Coatings with Given Functional Properties

Yar-Mukhamedova¹,

Ved²,

Сахненко³

et al. 2019

Applied Surface Science

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Ternary alloys of cobalt with molybdenum and tungsten deposited from biligand citrate-pyrophosphate electrolyte by pulsed mode exhibit different compositions and surface morphologies depending on current density and on/off time. The structure of binary and ternary alloys was found to be amorphous crystalline, and intermetallic phases Co 7 W 6 and Co 7 Mo 3 were identified in deposits. The coherent-scattering region size of the amorphous part was detected of 2-8 nm. The amorphous structure of ternary alloys and significant content of alloying elements (Mo and W) predetermine improved high corrosion resistance. Corrosion resistance of binary and ternary deposits increases with total content of refractory metals, which associated with molybdenum and tungsten, enhancing corrosion resistance to pitting as well as decreasing in roughness and smoothing out the relief of ternary coatings. Ternary galvanic alloys of cobalt with molybdenum and zirconium with micro-globular morphology with low level of stress and cracks are formed at a current density of 4-6Adm À2 and polarization on/off time 2/10 ms. High corrosion resistance of ternary coatings based on cobalt is caused by the increased tendency to passivity and high resistance to pitting corrosion in the presence of molybdenum and zirconium, as well as the acid nature of their oxides.

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The effect of electrodeposition conditions and post-annealing on nanostructure of Co–W coatings

Cited by 64 publications

References 37 publications

Electrodeposited tungsten-rich Ni-W, Co-W and Fe-W cathodes for efficient hydrogen evolution in alkaline medium

Electrodeposited tungsten-rich Ni-W, Co-W and Fe-W cathodes for efficient hydrogen evolution in alkaline medium

Evaluation of Corrosion and Tribological Behavior of Electrodeposited Tungsten Alloys

Composition Electrolytic Coatings with Given Functional Properties

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