Preparation of copper coated tungsten powders by intermittent electrodeposition

Xu, Jianguo; Yu, Gang; Hu, Bonian; Zhang, Jun; Dong, Qizhi; Zhang, XueYuan

doi:10.1016/j.powtec.2014.06.005

Cited by 20 publications

(5 citation statements)

References 29 publications

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“…instantaneous and progressive nucleations. [17][18][19][20] The dimensionless variables, (j/j m ) 2 vs. t/t m obtained from the experimental current transients were plotted with the theoretical curves for instantaneous and progressive nucleations (Fig. 3).…”

Section: Resultsmentioning

confidence: 99%

A mechanistic study on the effect of a surface protecting agent on electrocrystallization of silver nanoparticles

et al. 2014

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Cyclic voltammetry and chronoamperometry at characteristic potentials were employed to unravel the mechanism of electrocrystallization of silver nanoparticles (AgNPs) from their aqueous solution in the presence and absence of surface protecting agent tetrabutylammonium tetrafluoroborate (TBABF 4 ). The electrocrystallization parameters viz. initial current density (j 0 ), decay constant (s), diffusion coefficient (D) of Ag(I), number of active sites (N 0 ) and nucleation rate (a) were calculated by fitting the experimentally obtained current transients with the calculated current transients using a hybrid genetic algorithm (HGA).The theoretical currents were calculated from three popular electrocrystallization models viz. Scharifker and Mostany (SM), Sluyters-Rehbach, Wijenberg, Bosco and Sluyters (SRWBS) and Heerman and Tarallo (HT). Each of the three models fitted well by the HGA with the potentiostatic current transients observed at different potentials, both in the absence and in the presence of TBABF 4 with residual sum of squares ($10 À7 ) and reduced c 2 ($10 À10 ). However, the electrocrystallization parameters were distinctly different in each of the three models. Principal component analysis of the calculated parameters i.e. D, N S and aN 0 showed the absence of any correlation among the electrocrystallization parameters derived from the Scharifker and Hills (SH), SM, SRWBS and HT models. Further, the actual nuclei densities of the AgNPs, both in the presence and the absence of TBABF 4 , were found to be significantly higher than the predicted values from any of these models. Since these models are based on different empirical assumptions, one needs be careful in attaching any extra significance to the numerical values of j 0 , s, D, N 0 , "a" of any system only based on the quality of fitting. From the present data, it was conclusively proved that the surface protecting agent slowed down the kinetics of electrocrystallization due to introduction of a higher activation overpotential at the electrode-electrolyte interface and subsequent decreases in the number of nuclei on the electrode surface in the presence of TBA + ions, irrespective of the model.

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Section: Resultsmentioning

confidence: 99%

A mechanistic study on the effect of a surface protecting agent on electrocrystallization of silver nanoparticles

et al. 2014

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“…More generally, metal nanomaterials (e.g., NPs, nanowires, and nanotubes) can be electrodeposited through or not through a porous template onto an electrode surface from their metallic precursors (typically, soluble salts). Recently, Xu et al reported an intermittent electrodeposition method that allows electrodeposition of metal from its salt precursor onto conductive powders to form metal-coated powders . We noted that the existing electrochemical methods can only produce products either on an electrode surface, − in solution with a severely aggregated form, , or in solution with the aid of a surfactant stabilizer (the residual of which may contaminate the product and finally adversely affect its performance , ), still being uncompetitive to their counterpart of chemical synthesis in terms of yield and the capability in tuning of the morphology of the resultant product .…”

Section: Introductionmentioning

confidence: 99%

“…Recently, Xu et al reported an intermittent electrodeposition method that allows electrodeposition of metal from its salt precursor onto conductive powders to form metal-coated powders . We noted that the existing electrochemical methods can only produce products either on an electrode surface, − in solution with a severely aggregated form, , or in solution with the aid of a surfactant stabilizer (the residual of which may contaminate the product and finally adversely affect its performance , ), still being uncompetitive to their counterpart of chemical synthesis in terms of yield and the capability in tuning of the morphology of the resultant product . The major challenge in electrochemical synthesis of nanomaterials is the balance between the conductivity of the electrolyte solution and the colloidal stability of the as-synthesized nanomaterials when exposed in it …”

Section: Introductionmentioning

confidence: 99%

Collision Electrochemical Synthesis of Metal Nanoparticles Using Electrons as Green Reducing Agent

Sun

Cheng

et al. 2022

ACS Appl. Mater. Interfaces

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Synthesis of high-quality metal nanoparticles (NPs) is the premise toward their downstream diverse applications. Although some electrochemical synthesis strategies have been developed, the necessary use of high-concentration electrolyte solution as current pathway and reaction medium severely limits the colloidal stability of the growing NPs in the solution and their tunability in size and shape. Herein, we report a collision electrochemical method for the synthesis of metal NPs without the use of electrolyte solution. To this end, we designed an asymmetrical electrochemical cell to control the potential (i.e., to supply electrons) in the reaction system via a separated electrochemical cell, thereby enabling the electrochemical reaction occurring in an electrolyte-free growth solution. Consequently, this collision electrochemical method, using seed-mediated growth of NPs as examples, allows the synthesis of monodisperse homogeneous Au NPs and heterogeneous Pd-and Pt-coated Au NPs at a yield comparable to that achieved in common chemical synthesis. Furthermore, this method allows readily tailoring the morphology of the resultant metal NPs just by changing the concentration of the growth solution. Therefore, our green synthesis method is important for a variety of nanomaterials beyond metal NPs.

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“…Compared to the fluidized bed-based techniques, the electrochemical-based methods such as intermittent electrodeposition and electroless deposition are relatively straightforward, low-cost, and allow for the precise control of the process and coating properties. However, intermittent electrodeposition on particles was reported to result in both a substantial agglomeration of the coated powders and high surface roughness of the coating [ 43 , 44 ].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Processing and Thermal Properties of Functional Core/Multi-Shell ZnAl/Ni/NiP Microparticles

et al. 2021

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Electroless deposition on zinc and its alloys is challenging because of the negative standard potential of zinc, the formation of poor surface layers during oxidation in aqueous solutions, and extensive hydrogen evolution. Therefore, there are only few reports of electroless deposition on Zn and its alloys, neither of them on micro/nano powders. Here, we propose a two-step process that allows the formation of compact, uniform, and conformal Ni/NiP shell on Zn-based alloy microparticles without agglomeration. The process utilizes controlled galvanic displacement of Ni deposition in ethanol-based bath, followed by NiP autocatalytic deposition in an alkaline aqueous solution. The mechanism and effect of deposition conditions on the shell formation are discussed. Thermal stability and functional analysis of core-shell powder reveal a thermal storage capability of 98.5% with an encapsulation ratio of 66.5%. No significant morphological change of the core-shell powder and no apparent leakage of the ZnAl alloy through the Ni shell are evident following differential scanning calorimetry tests. Our two-step process paves the way to utilize electroless deposition for depositing metallic-based functional coatings on Zn-based bulk and powder materials.

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Preparation of copper coated tungsten powders by intermittent electrodeposition

Cited by 20 publications

References 29 publications

A mechanistic study on the effect of a surface protecting agent on electrocrystallization of silver nanoparticles

A mechanistic study on the effect of a surface protecting agent on electrocrystallization of silver nanoparticles

Collision Electrochemical Synthesis of Metal Nanoparticles Using Electrons as Green Reducing Agent

Electrochemical Processing and Thermal Properties of Functional Core/Multi-Shell ZnAl/Ni/NiP Microparticles

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