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Journal of Applied Electrochemistry

, Volume 13, Issue 3, pp 325–335 | Cite as

Aspects of the deposition of nickel on iron powder in a fluidized bed

  • L. Cifuentes
  • A. J. Fletcher
Papers

Abstract

An examination has been made of the effect of the composition, pH and the temperature of the solution on the deposition of nickel on iron in a fluidized bed that contained iron powder, solution and a fluidizing gas. In certain cases an electric potential was applied to electrodes contained within the bed, but otherwise the deposition process was spontaneous. Three different solutions were studied: nickel chloride, Watt's solution and nickel sulphamate. In the electroless case the highest and lowest deposition rates obtained under a specific set of experimental conditions were associated with the nickel chloride and nickel sulphamate solutions respectively. Even when an electric current was passed through the bed the spontaneous reactions dominated the process. The optimum pH was about 3.6; at other pH values the deposition of nickel was affected adversely by competitive cathodic reactions. The activation energies suggested that the deposition of nickel on iron powder was charge transfer controlled at temperatures below 60° C, but mixed diffusion and charge transfer control were operative at higher temperatures. The morphology of the coating was independent of the experimental conditions used, and always consisted of a nodular deposit giving incomplete coverage of the particles.

Keywords

Nickel Activation Energy Charge Transfer Iron Powder Cathodic Reaction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Nomenclature

A

area of deposition surface (m2)

c

nickel concentration in solution (kg m−3)

c0

initial nickel concentration in solution (kg m−3)

Eo

standard electrode potential (V)

k

rate constant (m s−1)

m

slope of Arrhenius plot (K)

Q

activation energy (J mol−1)

r

radius of powder particles (m)

R

gas constant (J mol−1 K−1)

T

temperature (K)

V

solution volume (m3)

A1

total surface area of powder (m2)

A2

corrected total surface area of powder (m2)

h

pit depth (m)

Mt

total mass of coated powder (kg)

N

number of particles

Np

number of pits per particle

r0

initial radius of particle (m)

r1

final (uncorrected) radius of particle (m)

r2

final corrected radius of particle (m)

rp

radius of pits (m)

VNi

volume of deposited nickel (m3)

V1

volume of deposited layer (m3)

Ni

quantity of nickel in coated powder (mass%)

ρNi

density of solid nickel (kg m−3)

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References

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Copyright information

© Chapman and Hall Ltd. 1983

Authors and Affiliations

  • L. Cifuentes
    • 1
  • A. J. Fletcher
    • 1
  1. 1.Department of MetallurgySheffield City PolytechnicSheffieldUK

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