Search for: electrodeposition
Total 172 records
Article International Journal of Modern Physics B ; Volume 22, Issue 18-19 , 2008 , Pages 3046-3059 ; 02179792 (ISSN) ; Dolati, A ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd 2008
The cobalt-nickel/copper multilayer films were prepared by electrodeposition process in sulfate solution using a three electrode cell. Cyclic voltammetry and double chronoampermetry techniques were utilized to characterize the multilayer system and to obtain the nucleation and growth mechanism. The cyclic voltammograms determined the reduction potential range of the three components and also clearly emphasized that electrodeposition of cobalt-nickel alloy was controlled by a kinetic process, while copper ions were reduced with diffusion-controlled mechanism. These results were confirmed with those which were extracted from the chronoampermetry curves. In addition, the current transients...
Electrochemical behavior of nanostructured fe-pd alloy during electrodeposition on different substrates, Article Journal of Electrochemical Science and Technology ; Volume 9, Issue 3 , 2018 , Pages 202-211 ; 20938551 (ISSN) ; Haghshenas, D. F ; Ghorbani, M ; Dolati, A ; Sharif University of Technology
Korean Electrochemical Society 2018
In this work, Fe-Pd alloy films have been electrodeposited on different substrates using an electrolyte containing [Pd(NH3)4]2+ (0.02 M) and [Fe-Citrate]2+ (0.2 M). The influences of substrate and overpotential on chemical composition, nucleation and growth kinetics as well as the electrodeposited films morphology have been investigated using energy dis-persive X-ray spectroscopy (EDS), current-time transients, scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) patterns. In all substrates – brass, copper and sputtered fluorine doped tin oxide on glass (FTO/glass) – Fe content of the electrodeposited alloys increases by increasing the overpotential....
Article International Journal of Modern Physics B ; Volume 22, Issue 18-19 , 2008 , Pages 3013-3022 ; 02179792 (ISSN) ; Dolati, A ; Kazemeini, M ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd 2008
The Co-Ni alloy nanowires were electrodeposited into porous anodic aluminum oxide (AAO) templates. At the first, highly ordered AAO templates were synthesized by two-step anodizing of aluminum to increase pore ordering. Arrays of nanowires with diameter about 30 nm and length about 5000 nm were electrodeposited by alternating current. The composition and structure property of nanowires were investigated by EDX, SEM and TEM techniques. It was found that nanowire composition was related to ions concentration in solution and it was shown that at the optimum potential range of electrodeposition (17-19 V), a change at the potential was shown no strong effect on chemical composition of nanowires....
Article Surface and Coatings Technology ; Volume 187, Issue 2-3 , 2004 , Pages 293-299 ; 02578972 (ISSN) ; Ghorbani, M ; Mazaheri, M ; Sharif University of Technology
The aim of this research is to obtain composite coatings of bronze (90% Cu-10% Sn) with graphite particles. The electrodeposition of G-Cu (Sn) composites from an alkaline bath containing cyanide is described. Composite coatings consisting of graphite particles and copper-tin were prepared by means of the conventional electrocodeposition (CECD) and sediment codeposition (SCD) techniques. The graphite particles involved were less than 10 μm. The dependence of graphite amount in the composite coatings was investigated in relation to the graphite concentration in bath, cathode current density, stir rate and technique type and it was shown that these parameters strongly affected the volume...
Electrodeposition of graphite-brass composite coatings and characterization of the tribological properties, Article Surface and Coatings Technology ; Volume 148, Issue 1 , 2001 , Pages 71-76 ; 02578972 (ISSN) ; Mazaheri, M ; Khangholi, K ; Kharazi, Y ; Sharif University of Technology
Co-deposition of Cu(Zn) and graphite powders with size less than 10 μ was studied. Electrocomposite coatings were prepared by means of the conventional electrodeposition (CECD) and the sediment co-deposition (SCD) techniques. Brass electroplating cyanide bath has been selected out of electrodeposition brass. The effect of parameters such as rate of agitation and current density on the composition of electrodeposition brass and also the effect of the concentration of graphite particles in brass bath, air agitation rate on graphite incorporation within brass matrix and deposition efficiency were studied. The wear and friction properties of G-Cu(Zn) composite coatings containing different...
Electrodeposited Rh and Rh-Cu Alloys as Ethanol-Tolerant Electrocatalysts for Oxygen Reduction in Alkaline Media, Article Electrocatalysis ; Volume 2, Issue 1 , December , 2011 , Pages 42-51 ; 18682529 (ISSN) ; Arab, R ; Sharif University of Technology
In this study, rhodium-copper alloys of different compositions are electrodeposited on graphite electrode from aqueous solutions. The bulk compositions of these alloys are determined using energy dispersive X-ray analysis and surface morphologies are investigated by scanning electron microscopy. The catalytic performance of these alloys in oxygen reduction reaction (ORR) in alkaline media is investigated by linear sweep voltammetry on rotating disk electrode assembly. The number of electrons transferred per O 2 molecule (n) obtained at different potentials is four indicating full reduction of oxygen to hydroxide ion. It is shown that Rh-Cu alloys are better electrocatalysts than Rh with...
MCDM selection of pulse parameters for best tribological performance of Cr–Al2O3 nano-composite co-deposited from trivalent chromium bath, Article Journal of Alloys and Compounds ; Volume 727 , 2017 , Pages 286-296 ; 09258388 (ISSN) ; Salehi Doolabi, M ; Sadrnezhaad, S. K ; Zafarani, H. R ; Salehi Doolabi, D ; AsadiZarch, M ; Sharif University of Technology
Optimum operating parameters for pulse co-deposition of nano-Al2O3 with Cr from a trivalent chromium bath onto Cu cathode are selected by using “technique for order performance by similarity to ideal solution” (TOPSIS), “VIšekriterijumsko KOmpromisno Rangiranje” (VIKOR), “elimination and choice expressing the reality” (ELECTRE) and “complex proportional assessment” (CORPAS) accompanied with analytic hierarchy processing (AHP) to compare methods for achievement of the best tribological coating performance. Criteria for appropriate selection include wear loss, corrosion resistance, micro-hardness, bath condition and current efficiency. Results ascertain the best Cr–Al2O3 nano-composite coating...
Electrochemical characterization of the Ni-Fe alloy electrodeposition from chloride-citrate-glycolic acid solutions, Article Materials Chemistry and Physics ; Volume 77, Issue 2 , 2003 , Pages 352-358 ; 02540584 (ISSN) ; Dolati, A. G ; Ghorbani, M ; Sharif University of Technology
Cyclic voltammetry and transient time (τ) measurements have been used to characterize the system, while potentiostatic I-t transients have been recorded to obtain the nucleation and growth mechanism. The electrodeposition of nickel, iron and nickel-iron alloys on the platinum was studied by electrochemical techniques in the presence of complexing compounds. The cyclic voltammetry results clearly show that the electrodeposition of nickel, iron and nickel-iron alloys is a diffusion-controlled process with a typical nucleation mechanism. The redox potentials of the Ni and Fe are shifted to more cathodic potentials in the complexing electrolytes. In addition, the current transients reveal that...
Simply tuned and sustainable cobalt oxide decorated titania nanotubes for photoelectrochemical water splitting, Article Applied Surface Science ; Volume 464 , 2019 , Pages 68-77 ; 01694332 (ISSN) ; Naseri, N ; Salehi, F ; Moshfegh, A. Z ; Sharif University of Technology
Elsevier B.V 2019
Effective utilization of solar energy is an urgent global issue for solving current environmental problems and the energy crisis. A challenging issue in water splitting for solar fuel production is developing high performance and scalable photo/electro catalysts using low cost approach. Here, CoO x nanostructures were grown on anodized TiO 2 nanotube arrays (TNAs) by amperostatic electrodeposition method as oxygen evolution reaction (OER) photoanodes. The effects of electrodeposition current density and deposition time on the growth of so-called nanostructures were investigated based on photoelectrochemical (PEC) measurements and structural characterizations. X-ray diffraction patterns of...
Article Journal of Alloys and Compounds ; Volume 476, Issue 1-2 , 2009 , Pages 234-237 ; 09258388 (ISSN) ; Arshadi, M. R ; Sharif University of Technology
This paper describes the effects of using direct and pulse current on composition and corrosion resistance of Fe-Ni-Cr alloy coatings. In both direct and pulse current electrodeposition, increasing the current density has a decreasing effect on Fe and Ni and an increasing influence on Cr. In pulse current electrodeposition, duty cycle has a greater effect than frequency on composition of the alloy coating, particularly in the range of 10-50%. In this range, by increasing the duty cycle, Ni decreases, Fe sharply increase and Cr shows an increasing trend. Following a study of the microhardness of coatings, it is determined that the microhardness increases about 1.5 times by pulse current...
The potentiostatic electrodeposition of gold nanowire/nanotube in HAuCl4 solutions based on the model of recessed cylindrical ultramicroelectrode array, Article Journal of the Electrochemical Society ; Volume 160, Issue 6 , 2013 , Pages D279-D288 ; 00134651 (ISSN) ; Dolati, A ; Siavash Moakhar, R ; Sharif University of Technology
The mechanism of gold nanowire (AuNW) and nanotube (AuNT) electrodeposition in a cyanide-free solution is investigated for the first time based on the analytical model of Szabo et al. (A. Szabo et al., J. Electroanal. Chem. 217 (1987) 417) for recessed cylindrical ultramicroelectrode (UME). Track-etched Polycarbonate Template (PCT) is served as cylindrical UME ensemble/arrays. Firstly, Au is nucleated through a charge transfer step and when the Nernst thickness exceeds the pore length, the radial diffusion is established around pore mouths. By overlapping of these domains, the planar diffusion toward the whole PCT surface is obtained. An analytic expression for global diffusion coefficient...
A study on the mechanism of electrodeposition of Ni/SiC composite coatings using impedance technique, Article ECS Transactions ; Volume 41, Issue 44 , 2012 , Pages 47-57 ; 19385862 (ISSN) ; 9781607683452 (ISBN) ; Dolati, A ; Electrodeposition; Sensor ; Sharif University of Technology
Ni/SiC nanocomposite coatings were electrodeposited using Watts type bath and different SiC particle size. The electrodeposition behavior of Ni/SiC nanoelectrocomposites was studied using electrochemical techniques such as impedance spectroscopy (EIS) and voltammetry. In this study it was shown that SiC particles modify the EIS diagram and voltammograms as well as surface morphology of electrodeposited layers. Experimental results showed that SiC particles not only affect the formation of intermediate species and decrease charge transfer resistance but also increase the nucleation sites for nickel electrodeposition and thus affect the microstructure of electrodeposited Ni/SiC nanocomposites....
Article ECS Transactions, 25 April 2010 through 30 April 2010 ; Volume 28, Issue 18 , April , 2010 , Pages 25-35 ; 19385862 (ISSN) ; 9781607681946 (ISBN) ; Dolati, A ; Hashemi Daryan, S ; Ghorbani, M ; Ghahramaninezhad, A ; Physical and Analytical Electrochemistry ; Sharif University of Technology
Platinum nanowires (PtNWs) were electrodeposited on the polycarbonate templates (PCTs) in aqueous solution of H2PtCl6 in triply distilled water. Nanowires with diameters of 50 and 100 nanometers were electrodeposited on the same condition. The kinetics of electrodeposition process was studied by electrochemical techniques such as voltammetry and chronoamperometry methods. Increasing the scan rate, the peaks shifted to more negative potentials and the current density also increased in each peak which was typical for a diffusion-control process. The potential range for the deposition of platinum nanowires was specified and consequently the potentiostatic i-t transients were utilized to produce...
Communication - Co-electrodeposition of Ni/SiO2(CH2)3SH composite: Modified Guglielmi’s model and mechanism of nucleation, Article Journal of the Electrochemical Society ; Volume 164, Issue 13 , 2017 , Pages E472-E474 ; 00134651 (ISSN) ; Rouhollahi, A ; Dolati, A ; Ghahramanifard, F ; Sharif University of Technology
Electrochemical Society Inc 2017
This work studies the influence of surface modification of silica nanoparticles by mercaptopropyl trimethoxysilane on silica weight percent in Ni coating during electrodeposition. Results showed SiO2(CH2)3SH particles were embedded in the Ni coating up to 11%. Also, modified Guglielmi’s model and mechanicsm of nucleation of Ni-SiO2(CH2)3SH composite were studied. © 2017 The Electrochemical Society. All rights reserved
M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem
Ni-P alloy coatings were electrodeposited using pulse current in a watt type bath in various conditions. The influences of different parameters were investigated and optimized for the highest amount of coating hardness using the Design Of Experiment (DOE) method. The optimized deposition parameters were current density 23.7 A/dm2, duty cycle 75%, frequency equal to 188 Hz, temperature equal to 70ºC and 17.5 gr/l of H3PO3. The DOE prediction of hardness for the optimized coatings was between 700 and 750 the achieved micro-hardness was about 725.8 HV. It was obtained that an increase of the current density will improve micro-hardness, decreases P content and increase deposition rate. Also, the...
Ph.D. Dissertation Sharif University of Technology ; Dolati, Abolghasem ; Ghorbani, Mohammad
Electrocodeposition of Ni-TiO2 nanocomposite single layers and Ni-TiO2/TiO2 multilayers from Watts bath containing TiO2 sol has been carried out on copper substrate. Cyclic voltammetry and chronoamperometry techniques were applied to study the influence of nickel sulfate and TiO2 sol concentrations on the electrochemical behavior of Ni-TiO2 deposition by direct current. The results clearly showed that at lower sulfate concentrations, the electrodepostion is a diffusion controlled process. Besides, the nucleation mechanism of the nanocomposites at low overpotentials followed the progressive system while at higher overpotentials, it was found to be instantaneous with three-dimensional growth...
M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad ; Dolati, Abolghasem
In this research a copper- diamond nanocomposite coating prepared by electrodeposition from a sulfate bath in order to increase the hardness and erosion resistance of cooper without disturbing cooper's specific physical properties as like as electrical and thermal conductivity. The mechanism of electrodeposition was analyzed with the technique of Cyclic Voltammetry, Chronopotentiometry and Chronoamperometry. The morphology, hardness, scratch resistance, elastic modulus and friction factor of coating were investigated by using a scanning electron microscope (SEM) and atomic force microscope(AFM) also the mechanism of co- deposition of diamond particles with copper was corresponded with...
M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem ; Afshar, Abdollah
Electrochemical supercapacitors are the charge-storage devices having high power density.The materials in the nano-size form with high surface area and high porosity give the best performances as the electrode materials for supercapacitors because of their distinctive characteristics of conducting pathways, and nanoscale dimensions. Therefore, the synthesis and the capacitive characterization of the high surface area nanomaterials such as nanotubes, nanowires,etc, have been carried out extensively in the past few years. In this research Polyaniline nanowires were electrochemically deposited on stainless steel electrode with the technique of Choronoamperometry and pulse Voltammetry and...
M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem
Platinum nanotubes were deposited inside the pores of polycarbonate template with the pore size of 200 nm by electrochemical methods. In this regard a solution containing of 0.05 M H2PtCl6 and 0. 1 M H2SO4 in doubly distilled water was utilized. The electrodeposition process was studied by electrochemical techniques such as voltammetry and chronoamperometry methods. It was observed that the process was conducted in several stages including; nucleation and growth in steady state regime. Furthermore, it was concluded that electrodeposition was affected by mass transport restriction and was controlled by a diffusion process. In this regard, all the voltammograms were shifted to more negative...
Electroplating and characterization of Cr–Al2O3 nanocomposite film from a trivalent chromium bath [electronic resource], Article Anti-Corrosion Methods and Materials ; Vol 61, No 4, 2014, 205-214 ; Sadrnezhaad, Khatiboleslam ; Salehi Doolabi, Davood ; Sharif University of Technology
The main aim of this study was to improve current efficiency and to obtain thicker coatings via aluminum oxide (Al2O3) addition to the chromium (Cr) (III) bath. Design/methodology/approach ‐ Pure Cr and nanocomposite Cr–Al2O3 coatings were electrodeposited from Cr (III) bath onto cathode copper substrates by conventional method. Dependence of current efficiency to current density, Al2O3 content and particle size were investigated. Findings ‐ Current efficiency increased with Al2O3 amount and decreased with Al2O3 particle size. Maximum current efficiency was achieved at 25 A/dm2 for pure Cr and 30 A/dm2 for composite coatings. Al2O3 bath content, current density and stirring rate increased...