Electrochemical study of nickel nucleation mechanisms on glassy carbon at different pH values in an industrial electrolyte

2021 ◽  
Vol 112 (2) ◽  
pp. 143-149
Author(s):  
Yangtao Xu ◽  
Zhenxu Zhu ◽  
Lubin Liu ◽  
Zhijian Liu
Keyword(s):  
Glassy Carbon ◽  
Electrode Surface ◽  
Growth Process ◽  
Three Dimensional ◽  
Spherical Shape ◽  
Nucleation And Growth ◽  
Nickel Ions ◽  
Fine Grained ◽  
Instantaneous Nucleation ◽  
Nucleation Mechanisms

Abstract The electrochemical behavior of nickel at different pH values in industrial electrolyte was investigated by means of cyclic voltammetry, chronoamperometry and scanning electron microscopy. The results show that the cathodic reaction of nickel ions on glassy carbon electrode surface in industrial electrolyte is a quasi-reversible nucleation and growth process controlled by diffusion. The process is carried out in a three-dimensional instantaneous nucleation and growth mode, and pH values only influence the growth process. The grain size decreased, the deposition rate increased and the density of deposition layer on electrode surface increased with the increase in pH. When the electrolyte pH is 4.8, the grains are uniformly distributed on the electrode surface in a spherical shape with the size of 80 nm, which is the optimum pH value for preparing fine-grained nano-nickel.

The effect of the variation of potential on progressive three-dimensional nucleation and growth

1978 ◽  
Vol 56 (5) ◽  
pp. 606-612 ◽  
Author(s):  
Stephen Fletcher ◽  
Arthur Smith
Keyword(s):  
Electrode Surface ◽  
Surface Coverage ◽  
Three Dimensional ◽  
Nucleation And Growth ◽  
Feedback Loops ◽  
Linear Potential ◽  
Applied Potential ◽  
Potential Sweep ◽  
Coverage Function

The effect of varying the applied potential during progressive three-dimensional nucleation and growth is described. The assumed model is that due to Armstrong, Fleischmann, and Thirsk in which expanding nuclei are considered to be right circular cones distributed at random on the electrode surface. The present work extends the previous potentiostatic approach by considering that the electrode surface coverage function responds instantaneously to small changes of applied potential. Under these circumstances we show that it is possible to calculate in an exact way the theoretical response of the model to various applied potential waveforms. In particular, the linear potential sweep and the staircase potential ramp are considered, as well as feedback loops generated by uncompensated ohmic overpotential. Certain limiting cases are derived which may be tested by experiment.

RESPONSE TO ASCORBIC ACID ON POLYPYRROLE FILM MODIFIED BY COPPER PARTICLES

2019 ◽  
Vol 26 (05) ◽  
pp. 1850187
Author(s):  
I. CHIKOUCHE ◽  
C. DEHCHAR ◽  
A. SAHARI ◽  
N. LOUCIF
Keyword(s):  
Ascorbic Acid ◽  
Modified Electrode ◽  
Three Dimensional ◽  
Deposition Process ◽  
Nucleation And Growth ◽  
Current Time ◽  
Force Microscopy ◽  
Atomic Force ◽  
Instantaneous Nucleation ◽  
Polypyrrole Film

In this work, a modified electrode of copper-polypyrrole (Cu-PPy) is elaborated by charging the polymer matrix by Cu particles. The response to ascorbic acid (AA) of this material was tested. The results show good performances. The results indicated a sensitive oxidation peak current of AA on the modified electrode. The success of this application led us to study the nucleation mechanism of copper on the PPy surface which permits to obtain this response. Nucleation and growth of electrodeposited copper onto PPy substrate have been studied in an aqueous solution of 0.01[Formula: see text]M CuCl2 and 1[Formula: see text]M KCl by means of electrochemical methods: cyclic voltammetry, chronoamperometry, and using atomic force microscopy (AFM). The model described by Scharifker and Hills was used to analyze current-time transients. According to this model, the nucleation and growth kinetics at the initial stages of deposition process involve an instantaneous nucleation followed by three-dimensional (3D) growth mechanism.

scholarly journals Electrochemical Nucleation and Growth Mechanism of Aluminum on AZ31 Magnesium Alloys

Coatings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 46
Author(s):  
Jinling Zhang ◽  
Yelei Li ◽  
Xiaomin Zhang ◽  
Yanchong Yu ◽  
Shebin Wang
Keyword(s):  
Diffusion Coefficient ◽  
Choline Chloride ◽  
Three Dimensional ◽  
Deep Eutectic Solvent ◽  
Nucleation And Growth ◽  
Electrochemical Nucleation ◽  
Diffusion Controlled ◽  
Instantaneous Nucleation ◽  
Apparent Diffusion ◽  
Al Coating

In this study, the nucleation and growth kinetics behavior of aluminum (Al) were investigated in the Choline-chloride (ChCl)-urea deep eutectic solvent (DES) ionic liquids. The studies of cyclic voltammetric and chronoamperometry demonstrated that the electrodeposition process of Al was controlled by three-dimensional progressive nucleation and instantaneous nucleation. And the growth of nuclei is a diffusion-controlled process. The diffusion coefficient of Al ions was calculated at 343 K, that is, 1.773 × 10−10 cm2/s. The Al coating was obtained on the surface of the AZ31 magnesium alloy electrode under appropriate conditions. According to the surface morphology of the Al film, it could be inferred that the theoretical deposit thickness is similar to the actual thickness, and the apparent diffusion rate of Al ions is slower than the diffusion coefficient in the electrolytes. So, in the later deposition, lamellar Al along the diffusion direction were formed, and lamellar depleted Al zones existed around the big grain Al-rich region.

Fundamental Research into Thin Films in a Developing Country

1972 ◽  
Vol 30 ◽  
pp. 500-501
Author(s):  
J.A. Eades ◽  
E. Grünbaum
Keyword(s):  
Thin Films ◽  
Growth Process ◽  
Empirical Process ◽  
Nucleation And Growth ◽  
Research Groups ◽  
Film Research ◽  
Fundamental Research ◽  
Controlled Deposition ◽  
The One ◽  
The University

In the last decade and a half, thin film research, particularly research into problems associated with epitaxy, has developed from a simple empirical process of determining the conditions for epitaxy into a complex analytical and experimental study of the nucleation and growth process on the one hand and a technology of very great importance on the other. During this period the thin films group of the University of Chile has studied the epitaxy of metals on metal and insulating substrates. The development of the group, one of the first research groups in physics to be established in the country, has parallelled the increasing complexity of the field.The elaborate techniques and equipment now needed for research into thin films may be illustrated by considering the plant and facilities of this group as characteristic of a good system for the controlled deposition and study of thin films.

Galvanostatic dissolution of mercury from the surface of glassy carbon into thiocyanate solution

1980 ◽  
Vol 45 (1) ◽  
pp. 169-178 ◽  
Author(s):  
František Opekar ◽  
Karel Holub
Keyword(s):  
Glassy Carbon ◽  
Electrode Surface ◽  
High Current Density ◽  
High Current ◽  
Nernst Equation ◽  
Potential Oscillations ◽  
Thiocyanate Solution ◽  
Theoretical Assumptions ◽  
Solution Proceeds ◽  
Dissolution Current

The galvanostatic dissolution of mercury from the surface of glassy carbon into a thiocyanate solution proceeds in accord with theoretical assumptions, as manifested by the constant product of the dissolution current and transition time. Under certain relations between the amount of oxidised mercury and concentration of thiocyanate at the electrode surface, however, a small part of the mercury dissolves at more positive potentials than correspond to the Nernst equation. This dissolution can be accompanied by potential oscillations. The anomalous behaviour is elucidated by the concept about coverage of a certain part of mercury with a film of sparingly soluble compounds of SCN- ions with mercury. This film is formed at the end of the galvanostatic dissolution on certain places of the electrode surface covered with mercury droplets, where SCN- ions are much exhausted as a result of a high current density.

scholarly journals Increase in Total Elongation Caused by Pure Shear Deformation in Ultra-Fine-Grained Cu Processed by Equal-Channel Angular Pressing

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 654
Author(s):  
Ryosuke Matsutani ◽  
Nobuo Nakada ◽  
Susumu Onaka
Keyword(s):  
Shear Deformation ◽  
Equal Channel Angular Pressing ◽  
Pure Shear ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Total Elongation ◽  
Local Deformation ◽  
Image Correlation ◽  
Fine Grained ◽  
Angular Pressing

Ultra-fine-grained (UFG) Cu shows little total elongation in tensile tests because simple shear deformation is concentrated in narrow regions during the initial stage of plastic deformation. Here, we attempted to improve the total elongation of UFG Cu obtained by equal-channel angular pressing. By making shallow dents on the side surfaces of the plate-like specimens, this induced pure shear deformation and increased their total elongation. During the tensile tests, we observed the overall and local deformation of the dented and undented UFG Cu specimens. Using three-dimensional digital image correlation, we found that the dented specimens showed suppression of thickness reduction and delay in fracture by enhancement of pure shear deformation. However, the dented and undented specimens had the same ultimate tensile strength. These results provide us a new concept to increase total elongation of UFG materials.

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