CATHODE SURFACE CHANGES IN THE PRESENCE OF GELATIN DURING ELECTRODEPOSITION OF COPPER

1943 ◽  
Vol 21b (6) ◽  
pp. 125-132 ◽  
Author(s):  
W. Gauvin ◽  
C. A. Winkler
Keyword(s):  
Grain Size ◽  
Current Density ◽  
Copper Sulphate ◽  
Cathode Surface ◽  
Active Area ◽  
Cathode Polarization ◽  
Active Centres ◽  
Main Factor ◽  
Surface Changes

Measurements of the cathode polarization during electrodeposition of copper from acid copper sulphate solutions indicate that introduction of gelatin into the electrolyte decreases the area of the cathode available for deposition, or active area, owing to adsorption of gelatin on the active centres. This decrease in area causes an increase in the true current density, with a resulting increase in cathode polarization, the former being assumed the main factor in causing an increase in the rate of nuclear formation and decrease in grain size.

AN INVESTIGATION ON THE EFFECT OF ELECTROCHEMICAL ADSORBATES ON PROPERTIES OF ELECTRODEPOSITED NANOCRYSTALLINE Fe–Ni ALLOYS

2013 ◽  
Vol 12 (01) ◽  
pp. 1350002 ◽  
Author(s):  
A. SANATY-ZADEH ◽  
K. RAEISSI ◽  
A. SAIDI
Keyword(s):  
Grain Size ◽  
Current Density ◽  
Cathode Surface ◽  
Iron Hydroxide ◽  
Ni Alloys ◽  
Fe Content ◽  
Iron Nickel ◽  
Current Densities ◽  
Eis Measurements ◽  
Deposition Current Density

Iron–Nickel nanocrystalline alloys were electrodeposited from a simple chloride bath using different current densities. The composition and grain size of deposited alloys were in the range of 29–42% Ni and 8–11 nm, respectively. The alloy deposited at lower current density showed higher microhardness, which is most probably due to its higher Fe content and lower grain size. EIS measurements showed that the iron hydroxide species can be formed and adsorbed onto the cathode surface during the deposition. Such species showed an inhibitive effect not only on Ni ion reduction but also on grain growth. By increasing the deposition current density, the adsorption tendency of iron hydroxide was reduced which caused an increase in grain size and Ni percentage of the alloy produced.

EFFECT OF GELATIN ON THE CHANGES IN INITIAL CATHODE POLARIZATION DURING ELECTRODEPOSITION OF COPPER

1954 ◽  
Vol 32 (6) ◽  
pp. 581-590 ◽  
Author(s):  
B. I. Parsons ◽  
C. A. Winkler
Keyword(s):  
Steady State ◽  
Current Density ◽  
Copper Sulphate ◽  
Chloride Concentration ◽  
High Current ◽  
Concentration Increase ◽  
Addition Agent ◽  
Cathode Polarization ◽  
Current Densities ◽  
Gelatin Concentration

In the absence of addition agent, the cathode polarization during initial electrolysis of copper from a solution of acid copper sulphate rose almost instantaneously from zero to approximately the steady state polarization. When gelatin was present in the electrolyte, the polarization generally increased to a maximum, Pmax, (in time tmax) then decreased to a minimum, Pmin, (in-time tmin) beyond which it increased to the steady state value, Ps. Generally, Pmax increased to a steady value with an increase in the time, T0, the electrode was in contact with the electrolyte before electrolysis was begun. At low, moderate, and high current densities respectively, tmax increased continuously, passed through a maximum, and decreased continuously with T0.The behavior of tmin approximately paralleled that of tmax. The polarization was linear in the logarithm of the current density; tmax and tmin decreased with increase in current density. The polarization values increased and tmax decreased, with increase in gelatin concentration. Increase of temperature had approximately the same effect as decrease in current density. With both chloride and gelatin present, Pmax was practically independent of T0 and chloride concentration, while Pmin and Ps showed minimum values at about 2 mgm./l. chloride.

EFFECT OF SURFACE ON CATHODE POLARIZATION DURING THE ELECTRODEPOSITION OF COPPER

1943 ◽  
Vol 21a (4) ◽  
pp. 37-50 ◽  
Author(s):  
W. Gauvin ◽  
C. A. Winkler
Keyword(s):  
Steady State ◽  
Current Density ◽  
Crystal Size ◽  
Cathode Surface ◽  
Surface Condition ◽  
Metal Structure ◽  
Polarization Current ◽  
Cathode Polarization ◽  
Current Densities ◽  
Effect Of Surface

Measurements in a modified Haring cell have shown that at current densities above approximately 0.6 amp. per dm.2, definite values of the cathode polarization are attained during the electrodeposition of copper from acid copper sulphate solutions, providing sufficient time is allowed for the cathode surface to attain a steady state corresponding to the conditions of electrolysis. At lower current densities, the base metal structure is perpetuated in the deposit, and the cathode polarization will depend upon the surface condition of the electrode initially. The results account for the lack of agreement in polarization values obtained by different workers using the Haring cell, and indicate that crystal size is fundamentally related to true current density, rather than to cathode polarization. A method is outlined for obtaining reproducible cathode-polarization–current-density curves, substantially corresponding to steady state values.

DEPOLARIZATION BY MERCAPTOACETIC ACID DURING ELECTRODEPOSITION OF COPPER

1956 ◽  
Vol 34 (2) ◽  
pp. 128-132 ◽  
Author(s):  
A. J. Sukava ◽  
C. A. Winkler
Keyword(s):  
Surface Area ◽  
Current Density ◽  
Copper Complex ◽  
Copper Sulphate ◽  
Mercaptoacetic Acid ◽  
Surface Roughening ◽  
Cathode Polarization ◽  
Sulphate Electrolyte ◽  
Consequent Increase

Mercaptoacetic acid (MAA) in acid copper sulphate electrolyte decreased the cathode polarization throughout the course of electrolysis at all concentrations up to 20 mgm./liter. Addition of small amounts of chloride caused further depolarization. When present together with cystine, MAA showed an independence of action. The depolarization caused by MAA was ascribed to a decreased activation overpotential due to substitution of a more readily dischargeable MAA–copper complex for the aquo–copper complex. The additional depolarization due to chloride was ascribed to formation of a still more readily dischargeable chloro–MAA–copper complex. The depolarization in both cases increased with time during prolonged electrolysis, apparently due to surface roughening with, presumably, a consequent increase in surface area and decrease in true current density.

RESTORATION OF MACHINE PARTS WITH GALVANIZED ZINC COATINGS

2020 ◽  
Vol 4 (141) ◽  
pp. 140-147
Author(s):  
MIKHAIL VIKHAREV ◽  
◽  
VLADIMIR YUDIN ◽  
VESELOVSKIY NIKOLAY ◽  
◽  
...  
Keyword(s):  
Current Density ◽  
Cathode Surface ◽  
Zinc Coating ◽  
Cathode Current Density ◽  
Research Purpose ◽  
Cathode Layer ◽  
Properties Of Coatings ◽  
Chemical Polarization ◽  
Cathode Current ◽  
Zinc Coatings

The article shows the role of electroplating in the restoration of parts, indicates the advantages of restoring parts with electroplating over other methods, and gives the characteristics and properties of coatings obtained by electroplating. (Research purpose) The research purpose is in increasing the speed of application of zinc electroplating when restoring parts. (Materials and methods) The cathode current density has a decisive influence on the coating speed. The main reason for limiting the cathode current density during galvanizing from sulfuric acid electrolytes is the chemical polarization of the cathode. The article presents a study on the designed installation for the application of galvanic coatings. When applying coatings to the internal surfaces of parts, there was used a device with activating elements having an electromechanical rotation drive. This device prevents depletion of the near-cathode layer of the electrolyte and reduces the chemical polarization of the cathode. Elements made of moisture-resistant skin were used as activators. (Results and discussion) The article presents the results of experiments as a dependence of the coating speed on the speed of the activator relative to the restoring surface. It also presents the relationship between the size of the abrasive grains of the activating elements, the force of their pressing against the cathode surface, the speed of movement of the activator and the speed of applying the zinc coating, as well as its quality. By activating the cathode surface, it was possible to raise the operating current density to 100-150 amperes per square decimeter. The speed of application of zinc coatings is 16-25 micrometers per minute. (Conclusions) In the course of research, authors determined the conditions of electrolysis during galvanizing, which provide a significant increase in the cathode current density and the rate of application of these coatings during the restoration of parts.

scholarly journals Effects of Flash Sintering Parameters on Performance of Ceramic Insulator

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1157
Author(s):  
Yong Liu ◽  
Xingwang Huang
Keyword(s):  
Grain Size ◽  
Electric Field ◽  
Field Intensity ◽  
Current Density ◽  
Electric Field Intensity ◽  
Unit Cell ◽  
Uniform Structure ◽  
Ceramic Insulator ◽  
Flash Sintering ◽  
Ceramic Insulators

Ceramic outdoor insulators play an important role in electrical insulation and mechanical support because of good chemical and thermal stability, which have been widely used in power systems. However, the brittleness and surface discharge of ceramic material greatly limit the application of ceramic insulators. From the perspective of sintering technology, flash sintering technology is used to improve the performance of ceramic insulators. In this paper, the simulation model of producing the ceramic insulator by the flash sintering technology was set up. Material Studio was used to study the influence of electric field intensity and temperature on the alumina unit cell. COMSOL was used to study the influence of electric field intensity and current density on sintering speed, density and grain size. Obtained results showed that under high temperature and high voltage, the volume of the unit cell becomes smaller and the atoms are arranged more closely. The increase of current density can result in higher ceramic density and larger grain size. With the electric field intensity increasing, incubation time shows a decreasing tendency and energy consumption is reduced. Ceramic insulators with a higher uniform structure and a smaller grain size can show better dielectric performance and higher flashover voltage.

THE EFFECT OF PREPARED PARAMETERS ON THE MICROSTRUCTURE OF ELECTRODEPOSITED NANOCRYSTALLINE NICKEL COATING

2004 ◽  
Vol 11 (04n05) ◽  
pp. 433-442 ◽  
Author(s):  
C. Y. DAI ◽  
Y. PAN ◽  
S. JIANG ◽  
Y. C. ZHOU
Keyword(s):  
Grain Size ◽  
Surface Morphology ◽  
Current Density ◽  
Crystal Orientation ◽  
Nickel Coating ◽  
Pulse Frequency ◽  
Lattice Parameter ◽  
Nanocrystalline Nickel ◽  
Peak Current Density ◽  
Peak Current

The nanocrystalline nickel coating was synthesized by pulse-jet electrodeposition from modified Watts bath. Pulse and jet plating was employed to increase the deposition current density, decrease diffusion layer, increase the nucleation rate and in this case the prepared method would result in fine-grained deposits. Transmission and scanning electron microscopy and X-ray diffraction (XRD) were used to study the microstructure, the surface morphology, the crystal preferred orientation and the variety of the lattice parameter respectively. The influence of pulse parameters, namely peak current density, the duty cycle and pulse frequency on the grain size, surface morphology, crystal orientation and microstructure was studied. The results showed that with increasing peak current density, the deposit grain size was found to decrease markedly in other parameters at constant. However, in our experiment it was found that the grain size increased slightly with increasing pulse frequency. For higher peak current density, the surface morphology was smoother. The crystal orientation progressively changed from an almost random distribution to a strong (111) texture. This means that the peak current density was the dominated parameter to effect the microstructure of electrodeposited nanocrystalline nickel coating. In addition, the lattice parameter for the deposited nickel is calculated from XRD and it is found that the calculated value is less than the lattice parameter for the perfect nickel single crystal. This phenomenon is explained by the crystal lattice mismatch.

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