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.

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.

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.

Electromigration in Al/W and Al(Cu)/W Interconnect Structures

1991 ◽  
Vol 225 ◽  
Author(s):  
C-K. Hu ◽  
P. S. Ho ◽  
M. B. Small ◽  
K. Kelleher
Keyword(s):  
Electron Microscope ◽  
Steady State ◽  
Scanning Electron Microscope ◽  
Drift Velocity ◽  
Current Density ◽  
Electron Microprobe ◽  
Temperature Range ◽  
Final Steady State ◽  
Current Densities ◽  
Scanning Electron

ABSTRACTThe electromigration drift velocity of Al in Al(3wt.% Si), Al(2wt.%Cu), and Al(2wt.%Cu,3wt.%Si) was measured in a temperature range 133 to 220 °C with current densities of 1.0 to 1.5×106A/cm2. In Al(3wt.% Si), a significant Al depletion at the cathode end and accumulation at the anode end of stripe were observed within a few hours at 1.5×106A/cm2 and 200°C. In addition, local hillocks and voids along the metal lines were observed. For Al(Cu,Si), the Al drift velocity was slowed down by Cu addition. The majority of hillocks started to grow at a distance about 6 μm away from the cathode end with current density of 1.5×106 A/cm2. The drift velocity of Al in Al(Cu,Si) was found to be a function of time starting with an initial low value and increasing to a an final steady-state value. The behavior was attributed to the migration of Cu and dissolution of Al2Cu precipitates. The activation energies of the depletion 3 Aμm of Al(2%,Cu, 3%Si) was determined to be 0.90±02 eV. The dissolution and growth of A12Cu in the tested samples of Ti/Al(2%Cu)/Ti/TiN were observed using the scanning electron microscope and an electron microprobe.

On: “Effect of surface polarization on resistivity modeling” by D. Guptasarma (GEOPHYSICS, v. 48, January 1983, p. 98–106).

Geophysics ◽  
1984 ◽  
Vol 49 (3) ◽  
pp. 314-314
Author(s):  
K. Duckworth
Keyword(s):  
Stainless Steel ◽  
Current Density ◽  
Low Frequency ◽  
Input Current ◽  
Steel Cylinder ◽  
Surface Polarization ◽  
Order Of Magnitude ◽  
Current Densities ◽  
A Current ◽  
Effect Of Surface

I am glad to see that this paper confirms the resistive behavior of metallic models when immersed in electrolyte and subject to low‐frequency currents, which my coauthor and I reported in 1978 (Saydam and Duckworth, 1978). It is also gratifying that this paper confirms the transition from resistive to conductive behavior with increase of frequency which we reported in that same paper. However, I must call into question the validity of the conclusions reached by the author of this paper. I do so for several reasons, the first of which is that the author is not entitled to display complex resistivity spectra derived in a model tank environment unless evidence is provided that those spectra are invariant for a range of primary currents extending over at least two decades from an upper limit of 1 mA. I say this because a current of 1 mA, as apparently used by the author, causes severe nonlinearity in tank modeling as my coauthor and I showed in 1978 (Saydam and Duckworth, ibid). In tests of stainless steel which we performed and in tests on pyrite performed by Anderson and Keller (1964) the maximum permissible current density for linear conditions to exist was [Formula: see text]. Current densities at the surface of the aluminum cylinder of 3 cm diameter used by the authors would have been as high as [Formula: see text] when it was located at a depth of 7 mm (as quoted) directly under one of the current electrodes if the delivered current was 1 mA. It seems unlikely that aluminum would behave linearly at current densities 32 times greater than the maximum permissible for either stainless steel or pyrite, but we have no way of knowing because this paper fails to provide any experimental evidence in this regard. However, in the case of the results for a vertical stainless steel cylinder shown by the author in Figure 6 we can readily compute that if a 1 mA input current was used, the current density at the surface of the cylinder closest to the [Formula: see text] electrode would have been [Formula: see text]. Thus, in this case, linearity could only have been ensured by using an input current at least an order of magnitude lower than the 1 mA quoted by the author.

Effect of Time on Corrosion Rates in Sulfuric Acid Predicted from Electrochemical Data

CORROSION ◽  
1970 ◽  
Vol 26 (2) ◽  
pp. 79-85 ◽  
Author(s):  
A. H. WAGNER ◽  
J. R. MYERS
Keyword(s):  
Steady State ◽  
Sulfuric Acid ◽  
Current Density ◽  
Corrosion Current Density ◽  
Acid Corrosion ◽  
Corrosion Current ◽  
Ternary Alloys ◽  
Corrosion Rates ◽  
Long Time ◽  
Current Densities

Abstract Effect of time on the cathodic polarization behavior of Ni, Cr, Ti, Al, and six Ni-Cr-Al and Ni-Cr-Ti alloys was determined in hydrogen saturated, 1N sulfuric acid at 22 C (71 F). Corrosion current densities (icorr) obtained for these specimens, using the beta-extrapolation technique, were generally found to be strongly time dependent. Corrosion current densities for Ni, Cr, and the six ternary alloys decreased with time and approached steady state values after about 72 hours exposure to the electrolyte. Corrosion current density for Al decreased markedly during the initial 24-hour period; further exposure did not appreciably affect the corrosion current density. The corrosion current density for titanium decreased only slightly as the exposure time was increased. All materials exhibited steady state corrosion current densities after sufficient exposure to the acid. Corrosion rates predicted using the steady state corrosion current densities correlated well with rates obtained from long time, weight loss tests. It was established that accurate corrosion rates can be predicted from electrochemical data only after steady state corrosion current densities have been obtained.

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

Electron-beam damage of oxides at high current densities

1989 ◽  
Vol 47 ◽  
pp. 634-635
Author(s):  
M. R. McCartney ◽  
J. K. Weiss ◽  
David J. Smith
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Current Density ◽  
Transition Metal Oxides ◽  
Time Resolved ◽  
Rapid Acquisition ◽  
Resolution Electron ◽  
Current Densities ◽  
Electron Stimulated Desorption ◽  
Channel Analyzer

It is well-known that electron-beam irradiation within the electron microscope can induce a variety of surface reactions. In the particular case of maximally-valent transition-metal oxides (TMO), which are susceptible to electron-stimulated desorption (ESD) of oxygen, it is apparent that the final reduced product depends, amongst other things, upon the ionicity of the original oxide, the energy and current density of the incident electrons, and the residual microscope vacuum. For example, when TMO are irradiated in a high-resolution electron microscope (HREM) at current densities of 5-50 A/cm2, epitaxial layers of the monoxide phase are found. In contrast, when these oxides are exposed to the extreme current density probe of an EM equipped with a field emission gun (FEG), the irradiated area has been reported to develop either holes or regions almost completely depleted of oxygen. ’ In this paper, we describe the responses of three TMO (WO3, V2O5 and TiO2) when irradiated by the focussed probe of a Philips 400ST FEG TEM, also equipped with a Gatan 666 Parallel Electron Energy Loss Spectrometer (P-EELS). The multi-channel analyzer of the spectrometer was modified to take advantage of the extremely rapid acquisition capabilities of the P-EELS to obtain time-resolved spectra of the oxides during the irradiation period. After irradiation, the specimens were immediately removed to a JEM-4000EX HREM for imaging of the damaged regions.

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.

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