Determination of the Diffusion Layer Thickness at a Cathode in CuSO[sub 4] Solutions

Tvarusko, Aladar; Watkins, L. S.

doi:10.1149/1.2407976

Cited by 29 publications

(22 citation statements)

References 5 publications

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“…The early works on two-beam interferometry in electrochemistry were reviewed by Muller [1]. Different interferometers such as Rayleigh [2,3], Jamin [4,5] and Mach-Zehnder [6][7][8] have been used to study the concentration field during electrochemical processes. The ionic mass-transfer rate was first examined by Ibl's group [9] by means of a Jamin interferometer.…”

Section: Introductionmentioning

confidence: 99%

“…A great deal of work [4][5][6][7][8][9][19][20][21][22][23][24][25][26][27] has been devoted to the interferometric analysis of the concentration profiles developing during the electrolysis of CuSO 4 solution between vertical electrodes. This indeed constitutes a typical problem due to the numerous analytical solutions and scaling predictions available from the analogous problems in heat transfer (two sidewalls (i) either at constant, but different temperatures or (ii) exposed to a constant heat flux).…”

Section: Introductionmentioning

confidence: 99%

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The concentration field during transient natural convection between vertical electrodes in a small-aspect-ratio cell

Yang

Eckert

Heinze

et al. 2008

Journal of Electroanalytical Chemistry

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The concentration field during transient natural convection between vertical electrodes in a small-aspect-ratio cell

Yang

Eckert

Heinze

et al. 2008

Journal of Electroanalytical Chemistry

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“…The change of the refractive index at the cathode/solution interface, • during the current flow is obtained by multiplying the refractive index gradient with the diffusion layer thickness (2,3). The change of the refractive index at the cathode/solution interface, • during the current flow is obtained by multiplying the refractive index gradient with the diffusion layer thickness (2,3).…”

Section: Resultsmentioning

confidence: 99%

“…The optical path length change of the reflected ray was measured as a function of time, incidence angle, and electrode displacement (2). The change of refractive index is obtained by multiplying the refractive index gradient with the diffusion layer thickness (2,3). The change of refractive index is obtained by multiplying the refractive index gradient with the diffusion layer thickness (2,3).…”

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confidence: 99%

Interferometric Study of the Concentration Change at High Cathodic Current Densities

Tvarusko¹,

Watkins²

1971

J. Electrochem. Soc.

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The refractive index change, An, i.e., the concentration of the solution at a vertical cathode was studied by a Lloyd mirror laser interferometer during the electrodeposition of copper from CuSO4 solutions with and without tenfold excess of H2SO4. The initial galvanostatic transients were studied below the limiting current density and above to the start of H~ bubble formation. It was found that the concentration decreased linearly with it I/2 for both solu-* Electrochemical Society Active Member. 1Present address: current-potential curves thus obtained provide quantitative values of Tafel slopes, exchange current densities, reaction orders, apparent heats of activation, and, under favorable conditions, stoichiometric numbers. In addition to these parameters, a great deal of ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.255.6.125 Downloaded on 2015-03-13 to IP

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“…The ratio of sum of squares due to regression to the total sum of squares was calculated to be 0.998. concerning the properties of phthalocyanines (2)(3)(4)(5), namely, electrochemical and chemical redox equilibria (6)(7)(8), suggests a reversible reduction of up to four electrons per molecule. The apparent discrepancies gave rise to a more detailed investigation of the electrochemistry of the cell.…”

Section: Appendixmentioning

confidence: 99%

Measurement of Concentration Profiles of Cu2+ Ion and H+ Ion near a Plane Vertical Cathode by Two‐Wavelength Holographic Interferometry

Denpo

Okumura

Fukunaka

et al. 1985

J. Electrochem. Soc.

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A technique of two-wavelength holographic interferometry was applied to simultaneously measure the concentration profiles of Cu 2~ ion and H + ion near a plane vertical cathode placed in an unstirred aqueous solution containing CuSO4 and excess H2SO4. It was revealed that the measured concentration profiles of Cu 2+ ion and H + ion are approximated with the parabolic equations of horizontal distance from cathode surface and that the concentration gradient of Cu 2+ ion at the cathode surface is larger in CuSO4-H2SO4 solution than in CuSO4 solution at the same cathodic current density and vertical distance. The following matters were also clarified: (i) the nondimensional rate of ionic mass transfer is shown as a function of Ray]eigh number based on the boundary layer theory, and (ii) the effect of the addition of excess H2SO4 is expressed by a parameter f which is the ratio of Rayleigh numbers in CuSO4-H2SO4 solution and in CuSO4 solution under the conditions of the uniform distribution of cathodic current density and an excess of H2SO4.The measurement of cathodic concentration profile of ion is important for elucidating not only the ionic mass transfer itself, but also the effect of supporting electrolyte (1, 2). The optical methods such as Jamin (3), Mach-Zehnder (4), and holographic interferometry (5, 6) are effective for the measurement in the single-component aqueous solutions because of the proportionality between the ionic concentration and the refractive index of the solution.In the industrial electrolysis, such as the electrolytic refining of copper, for example, an excess of sulfuric acid is added. In the multicomponent aqueous solutions, the above proportionality no longer holds and the measurement of concentration profiles of ions becomes more difficult.An experimental technique using an image sensor of one-dimensional photodiode array was developed in order to measure the concentration profile of Cu ~+ ion in aqueous CuSO4-H2SO4 solution (7). In this measurement of the light absorbance distribution, however, a noise caused by the light diffraction near the cathode surface was superimposed on the output signal, and the concentration of Cu 24 ion on the cathode surface was estimated by extrapolating the profile toward the cathode surface. The estimation of the concentration of H + ion on the cathode surface was tried by subtracting the light absorbance due to Cu 2+ ion from the refractive index of the solution measured by the conventional holographic interferometry (5). Due to the error of the measurements and the extrapolation, however, the precision and accuracy of the estimated H + ion concentration was relatively poor.It is the intent of the present work to carry out the simultaneous measurement of concentration profiles of Cu 2+ ion and H + ion in the cathodic boundary layer by using a technique of two-wavelength holographic interferometry which is based on the dispersion effect of refractive index of the solution. The problem due to diffraction pattern appearing near the cathode surface can be avo...

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Determination of the Diffusion Layer Thickness at a Cathode in CuSO[sub 4] Solutions

Cited by 29 publications

References 5 publications

The concentration field during transient natural convection between vertical electrodes in a small-aspect-ratio cell

The concentration field during transient natural convection between vertical electrodes in a small-aspect-ratio cell

Interferometric Study of the Concentration Change at High Cathodic Current Densities

Measurement of Concentration Profiles of Cu2+ Ion and H+ Ion near a Plane Vertical Cathode by Two‐Wavelength Holographic Interferometry

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