scholarly journals Copper deposits obtained by pulsating overpotential regime with a long pause and pulse duration from sulfated solutions

2020 ◽  
Vol 85 (6) ◽  
pp. 795-807
Author(s):  
Fatemeh Shafiei ◽  
Kourosh Jafarzadeh ◽  
Ali Madram
Keyword(s):  
Current Density ◽  
Sem Analysis ◽  
Diffusion Current ◽  
Electron Microscopic ◽  
Copper Deposits ◽  
H2so4 Concentration ◽  
Scanning Electron Microscopic ◽  
Polarization Characteristics ◽  
Pulsating Overpotential ◽  
Limiting Diffusion Current

The morphologies of the copper deposits obtained by pulsating overpotential regime with prolonged pulse and pause durations from the solution of 0.15 M CuSO4 in 0.50 M H2SO4 at overpotentials lower, higher and belonging to the plateau of limiting diffusion current density were compared with those obtained by the same electrodeposition regime from solutions of 0.075 and 0.30 M CuSO4 in 0.50 M H2SO4 and 0.15 M CuSO4 in 0.25 and 1.00 M H2SO4 at overpotentials outside the plateau of limiting diffusion current density. These samples were characterized by scanning electron microscopic (SEM) analysis and the cathodic polarization characteristics from solutions compared. Increasing the Cu(II) concentration led to an increase in the limiting diffusion current density. Decreasing the H2SO4 concentration shifts both beginning and the end of the plateau of the limiting diffusion current density towards higher electrodeposition overpotentials. Also, electrodeposition in solutions of 0.15 M CuSO4 in 0.25 and 1.00 M H2SO4 led to the formation of morphological forms of copper deposits characteristic for electrodeposition of copper from higher CuSO4 or lower H2SO4 in solution at some higher overpotentials.

scholarly journals Effect of temperature on the electrodeposition of disperse copper deposits

2007 ◽  
Vol 72 (12) ◽  
pp. 1369-1381 ◽  
Author(s):  
Nebojsa Nikolic ◽  
Ljubica Pavlovic ◽  
Miomir Pavlovic ◽  
Konstantin Popov
Keyword(s):  
Current Density ◽  
Sem Analysis ◽  
Diffusion Current ◽  
Effect Of Temperature ◽  
Electron Microscopic ◽  
Copper Deposits ◽  
Disperse Copper ◽  
Average Current ◽  
Limiting Diffusion Current

The effect of temperature on the electrodeposition of copper at overpotentials belonging to the plateau of the limiting diffusion current density and higher was examined by the determination of the average current efficiency of hydrogen evolution and by scanning electron microscopic (SEM) analysis of the morphology of the formed copper deposits. Increasing the temperature of the solution led to a shift of both the beginning and the end of the plateau of the limiting diffusion current density towards lower electrodeposition overpotentials. Also, higher temperatures led to the formation of morphological forms of copper deposits characteristic for electrodeposition of copper at some higher overpotentials. The unexpected trend in the development of copper structures electrodeposited at an overpotential of 800 mV is discussed in terms of the effect of temperature on the viscosity and surface tension of the electroplating solution.

scholarly journals Estimation of the exchange current density and comparative analysis of morphology of electrochemically produced lead and zinc deposits

2017 ◽  
Vol 82 (5) ◽  
pp. 539-550
Author(s):  
Nebojsa Nikolic ◽  
Predrag Zivkovic ◽  
Goran Brankovic ◽  
Miomir Pavlovic
Keyword(s):  
Current Density ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Diffusion Current ◽  
Electron Microscopic ◽  
Zinc Electrodeposition ◽  
Lead And Zinc ◽  
Current Densities ◽  
Limiting Diffusion Current ◽  
Zinc Deposits

The processes of lead and zinc electrodeposition from the very dilute electrolytes were compared by the analysis of polarization characteristics and by the scanning electron microscopic (SEM) analysis of the morphology of the deposits obtained in the galvanostatic regime of electrolysis. The exchange current densities for lead and zinc were estimated by comparison of experimentally obtained polarization curves with the simulated ones obtained for the different the exchange current density to the limiting diffusion current density ratios. Using this way for the estimation of the exchange current density, it is shown that the exchange current density for Pb was more than 1300 times higher than the one for Zn. In this way, it is confirmed that the Pb electrodeposition processes are considerably faster than the Zn electrodeposition processes. The difference in the rate of electrochemical processes was confirmed by a comparison of morphologies of lead and zinc deposits obtained at current densities which corresponded to 0.25 and 0.50 values of the limiting diffusion current densities.

scholarly journals Comparative analysis of the polarization and morphological characteristics of electrochemically produced powder forms of the intermediate metals

2014 ◽  
Vol 33 (2) ◽  
pp. 169 ◽  
Author(s):  
Nebojsa D. Nikolic ◽  
Predrag M. Zivkovic ◽  
Bojan Jokic ◽  
Miomir G. Pavlovic ◽  
Jasmina S. Stevanovic
Keyword(s):  
Surface Morphology ◽  
Current Density ◽  
Morphological Characteristics ◽  
Copper Surface ◽  
Diffusion Current ◽  
Copper Electrodeposition ◽  
Continuous Change ◽  
Polarization Characteristics ◽  
High Overpotentials ◽  
Limiting Diffusion Current

The polarization and morphological characteristics of powder forms of the group of the intermediate metals were examined by the analysis of silver and copper electrodeposition processes at high overpotentials. The pine-like dendrites constructed from the corncob-like forms, very similar to each others, were obtained by electrodeposition of these metals at the overpotential belonging to the plateaus of the limiting diffusion current density. The completely different situation was observed by electrodeposition of silver and copper at the overpotential outside the plateaus of the limiting diffusion current density in the zone of the fast increase of the current density with the overpotential. The silver dendrites, very similar to silver and copper dendrites obtained inside the plateaus of the limiting diffusion current density, were obtained at the overpotential outside the plateau. Due to the lower overpotential for hydrogen evolution for copper, hydrogen produced during copper electrodeposition process strongly affected the surface morphology of copper. The same shape of the polarization curves with the completely different surface morphology of Cu and Ag electrodeposited at overpotentials after the inflection point clearly indicates on the importance of morphological analysis in the investigation of polarization characteristics of the electrodeposition systems. Role of hydrogen as crucial parameter in the continuous change of copper surface morphology from dendrites to the honeycomb-like structures was investigated in detail. On the basis of this analysis, the transitional character of the intermediate metals between the normal and inert metals was considered. The typical powder forms characterizing electrodeposition of the intermediate metals were also defined and systematized.

Development of an Aging Process for Friction Stir Extruded Joints

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Adam W. Jarrell ◽  
Brayden C. Terry ◽  
Alvin M. Strauss ◽  
George E. Cook
Keyword(s):  
Heat Treatment ◽  
Aging Process ◽  
Dissimilar Materials ◽  
Sem Analysis ◽  
Post Processing ◽  
Electron Microscopic ◽  
Friction Stir ◽  
Hardening Process ◽  
Scanning Electron Microscopic ◽  
Friction Stir Extrusion

Abstract Friction stir extrusion is a derivative process of friction stir welding for joining dissimilar materials. The process forms a mechanical joint through extrusion to form interlocking features between two metals. When joining AA6061-T6 to mild steel through extrusion of a dovetail, much of the T6 heat treatment of the aluminum in and around the weld is lost during the process. This paper details the examination of a post-processing aging process to return AA6061 to the T6 condition. Through a 10-h precipitation hardening process at 170 °C. The welds experienced a 23.9% increase in the tensile strength from 2193 N as-welded to 2718 N after 10 h. Hardness measurements showed a return close to T6 conditions in both the weld nugget and extruded material, 67.5–83.5 HRF and 54.7–81.8 HRF, respectively, during the heat treatment period. The steel showed no substantial changes in hardness during the heat treatment. Scanning electron microscopic (SEM) analysis revealed significant changes in the sizes of two species of inclusions within the aluminum during both the welding and post-processing.

scholarly journals The ionic equilibrium in the CuSO4-H2SO4-H2O system and the formation of the honeycomb-like structure during copper electrodeposition

2008 ◽  
Vol 73 (7) ◽  
pp. 753-760 ◽  
Author(s):  
Nebojsa Nikolic ◽  
Ljubica Pavlovic ◽  
Goran Brankovic ◽  
Miomir Pavlovic ◽  
Konstantin Popov
Keyword(s):  
Hydrogen Evolution ◽  
Current Density ◽  
Diffusion Current ◽  
Copper Electrodeposition ◽  
Hydrodynamic Conditions ◽  
Ionic Equilibrium ◽  
Electrode Layer ◽  
Limiting Diffusion Current

The ionic equilibrium of the species in the CuSO4-H2SO4-H2O system was employed to systematize the conditions of copper electrodeposition leading to the formation of the honeycomb-like structure. The reason why CuSO4 concentrations higher than 0.15 M are unsuitable for the formation of honeycomb-like structures is shown. The range of H2SO4 concentrations enabling the formation of this type of structure was also determined. The conditions leading to the formation of the honeycomb-like structures are: electrodeposition from solutions with lower concentrations of Cu(II) ions (0.15 M CuSO4 and less) in a concentration range from 0.25 to 1.0 M H2SO4, at a temperature of 18.0?1.0 ?C and at overpotentials outside the plateau of the limiting diffusion current density at which hydrogen evolution is vigorous enough to change the hydrodynamic conditions in the near-electrode layer. .

scholarly journals Effect of orientation of initially formed grains on the final morphology of electrodeposited lead

2014 ◽  
Vol 79 (8) ◽  
pp. 993-1005 ◽  
Author(s):  
Nebojsa Nikolic ◽  
Konstantin Popov ◽  
Evica Ivanovic ◽  
Goran Brankovic
Keyword(s):  
Growth Process ◽  
Sem Analysis ◽  
Diffusion Control ◽  
Lateral Side ◽  
Electron Microscopic ◽  
Initial Shape ◽  
Hexagonal Shape ◽  
Initial Stage ◽  
Scanning Electron Microscopic ◽  
Spherical Diffusion

The processes of Pb electrodeposition in the diffusion control were examined by the scanning electron microscopic (SEM) analysis of the formed crystals. Orientation of grains of hexagonal shape formed in the initial stage of electrodeposition strongly affected the final morphology of Pb crystals. Formation of Pb crystals of the different shape from the same initial shape was discussed by the effect of orientation of initially formed grains on the type of diffusion control. The spherical diffusion layer was formed around the tip of the hexagonal shaped grain oriented by the tip towards the bulk of solution leading to formation of elongated crystals in the growth process. On the other hand, the cylindrical type of diffusion was responsible for growth of hexagonal shaped grains oriented by the lateral side towards the bulk of solution. Pb crystals with well defined sides parallel to the surface area of macroelectrode were formed by this type of diffusion.

scholarly journals Exploration of Thread for their Possible use in Fabrication of Low Cost Diagnostic Microfluidic Device

2018 ◽  
Vol 15 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Rakesh B Kabariya ◽  
Vimal M Ramani
Keyword(s):  
Capillary Flow ◽  
Low Cost ◽  
Sem Analysis ◽  
Absorption Capacity ◽  
Great Promise ◽  
Diagnostic Purpose ◽  
Electron Microscopic ◽  
Cotton Thread ◽  
Scanning Electron Microscopic ◽  
The Ideal

The emerging concept of thread-based microfluidics has shown great promise for application to inexpensive disease detection and environmental monitoring. This paper describe the properties of thread for the development of thread based low-cost microfluidics device for the diagnostic, food safety and environmental assay. Various properties of thread like capillary flow, wicking capacity and absorption capacity, make them important to fabricate the low-cost microfluidics device. In this paper, three different thread sample viz. cotton yarn, cotton thread and spun thread were taken and different properties like wicking capacity, fluid capillary flow, absorption capacity were measured as well as Scanning Electron Microscopic (SEM) analysis of the same was also carried out to study the morphology and texture of thread fibers. Data obtained from result indicate that the cotton thread having all the ideal characteristic to fabricate the diagnostic device and thus it is suitable for the fabrication of thread based microfluidics device for the diagnostic purpose.

TAGUCHI GREY RELATIONAL MULTI-RESPONSE EXPERIMENTAL OPTIMIZATION ON MODIFICATION OF Al-6061 SURFACE USING Si–Cu GREEN COMPACT TOOL IN EDM

2021 ◽  
pp. 2150073
Author(s):  
RASHED MUSTAFA MAZARBHUIYA ◽  
BHARGAB MADHAB BARUA ◽  
MANESWAR RAHANG
Keyword(s):  
Surface Modification ◽  
Sem Analysis ◽  
Green Compact ◽  
Electron Microscopic ◽  
Work Surface ◽  
Optical Micrograph ◽  
Material Deposition ◽  
Scanning Electron Microscopic ◽  
Grey Relational ◽  
Pulse On Time

This paper presents the surface modification of aluminium-6061 by electric discharge machining (EDM). Si–Cu powder metallurgical green compact tool is used to deposit its material on to the work surface under reverse polarity of EDM. Compact load, current and pulse on-time are selected control parameters. Material deposition rate (MDR), tool wear rate (TWR) and surface roughness ([Formula: see text] are considered as process outputs. Scanning electron microscopic (SEM) analysis and energy dispersive X-ray (EDX) analysis show the presence of tool materials in the deposit of work surface. Olympus optical micrograph shows an average thickness of the deposited layer to be 18.73[Formula: see text][Formula: see text]m. The hardness of the deposited layer is found to be 268[Formula: see text]HV. Analysis of variance (ANOVA) shows the compact load to be the most effective parameter on surface modification followed by pulse on-time and current, respectively.

scholarly journals Synthesis and Characterization of P3HT/Metal Nanoparticles

2019 ◽  
Vol 17 (43) ◽  
pp. 122-127
Author(s):  
Mustafa A. Mustafa
Keyword(s):  
Metallic Nanoparticles ◽  
Chemical Interaction ◽  
Pulsed Laser ◽  
Sem Analysis ◽  
Electron Microscopic ◽  
X Ray ◽  
Spherical Structure ◽  
Scanning Electron Microscopic ◽  
Fabrication And Characterization

In this work the fabrication and characterization of poly(3-hexylthiophene) P3HT-metallic nanoparticles (Ag, Al). Pulsed Laser Ablation (PLA) technique was used to synthesis the nanoparticles in liquid. The Fourier Transformer Infrared (FTIR) for all samples indicate the chemical interaction between the polymer and the nanoparticles. Scanning Electron Microscopic (SEM) analysis showed the particle size for P3HT-AgNps samples between 44.50 nanometers as well the spherical structure. While for P3HT-AlNps samples was flakes shape. Energy Dispersive X-ray (EDX) spectra show the existing of amount of metallic nanoparticles.

Mechanism of PVC’s Solid-Phase Photocatalytic Degradation Enhanced by Plasma

2007 ◽  
Vol 544-545 ◽  
pp. 155-158
Author(s):  
Xiao Jing Li ◽  
Guan Jun Qiao ◽  
Jie Rong Chen
Keyword(s):  
Free Radicals ◽  
Photocatalytic Degradation ◽  
Solid Phase ◽  
Ambient Air ◽  
Nitrogen Plasma ◽  
Sem Analysis ◽  
Electron Microscopic ◽  
Pvc Film ◽  
Spin Resonance ◽  
Scanning Electron Microscopic

The solid-phase photocatalytic degradation of poly (vinyl chloride) (PVC) films was investigated in ambient air. The photodegradation of the PVC and PVC-TiO2 was compared with that of plasma-treated PVC and plasma-treated PVC-TiO2 performing a weight loss monitoring and scanning electron microscopic (SEM) analysis. The SEM of the PVC-TiO2 film treated by plasma showed many cracks on the surface after photodegradation. Furthermore, the surface wettability and surface structure of PVC after nitrogen plasma treatment was characterized by contact angle, surface tension, and electron spin resonance (ESR). The experiment indicated that the surface free energy and wettability of PVC treated by plasma increased greatly. ESR revealed that the signal of radicals on the surface of the plasma-treated PVC film was enhanced after treatment. The free radicals on the surface of plasma-treated PVC possibly decreased the activating energy of photocatalytic reaction, which belongs to the free radicals reaction, because the chemical activity of the free radicals was high. According to these findings, a mechanism on the photodegradation of plasma-treated PVC-TiO2 is proposed.

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