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Electrochemical Characterization of Qraphene-based Cathode Electrode for Lithium-air Battery
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
The air cathode of li-air batteries has been identified as a key factor affecting the overall performance of Li-air batteries. Graphene-based cathodes have been investigated as cathode catalysts for lithium-air batteries due to their high activity in accelerating and facilitating oxygen reduction reaction (ORR). In this study at first, graphene oxide was synthesized using Hummers’ method, and then it has been reduced via hydrothermal methode. To increase electrocatalytic properties of the sample Cobalt oxide nanoparticles has been precipitated on reduced graphene oxide, and it has also been doped with Nitrogen. Three samples of reduced graphene aerogel (GA), Nitrogen doped graphene aerogel...
Deposition and Properties of ZIF-8/SiO2 Hydrophobi Anti-Corrosion Coating
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
In this research, a coating was created on the steel surface using the network structure of zeolite imidazolate-8 (ZIF-8) and its effect on the corrosion behavior of steel was investigated. Then, the effect of two coupling agents, mercaptopropyltriethoxysilane (MPTES) and aminopropyltriethoxysilane (APTES) on the coating and its anti-corrosion properties was investigated. Then, in order to make a hydrophobic coating, the substrate was first coated with ZIF-8 and then a combination of silica nanoparticles plus hexamethyldisilazane (HMDS) and polymethylhydrogensiloxane (PMHS) was added to the initial solution and then coating was done. As a result of this process, the contact angle of water...
Synthesis and Investigation of Properties of Intumescent Fireproofing Paint with Oxide Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
Intumescent paints are coatings designed for passive fire protection of steel and other materials. In this research, the performance of water-based intumescent coating with vinyl acetate resin for cellulose fire conditions and epoxy-based coatings for hydrocarbon fire conditions has been investigated. The fire resistance of coatings was evaluated according to the ASTM E119 standard for water-based coating and UL1709 standard for epoxy-based intumescent coating. For the water-based intumescent coating, the expansion of char was investigated in a furnace with a temperature of 800°C for 1 hour. Thermal decomposition was studied by thermogravimetric analysis (TGA). Also, flammability was...
Electrodeposition of Platinum Nanowires
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor) ; Ghorbani, Mohammad (Supervisor)
Abstract
Platinum nanowires were prepared by electrodeposition in polycarbonate membrane, with different average diameter of nanowires about 15, 50 and 100 nm and the height about 6 µm. Kinetics of electrodeposition process were studied by electrochemical techniques such as voltammetry and chronoamperometry methods. Diffusion coefficient was then calculated from the electrochemical parameters and consequently the density of primer nuclei was extracted. The morphology of Pt nanowires was characterized by SEM, TEM and EDX. The results show that growing Nanowires on the surface of template is branch-like. The electro-oxidation of methanol and hydrogen on this electrode is investigated at room...
Investigation Increasing Corrosion Resistance of Reinforcement in Concrete
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
corrosion of steel reinforcements in concrete is one of the most important reasons for durability reduction of offshore structures. To reduce the diffusion rate of ion reactivity in concrete and its reinforcement surface, different methods such as chemical change and coating of reinforcement and concrete are used. In this research for increase corrosion resistance, effect of Pozzolanic additive materials such as fly ash and micro silica , in optimized percentages, 25% and 10% by weight of cement respectively, the percentage of polypropylene fibers improved 2.5% volume of concrete and Ferrogard-901 industrial inhibitor with 3% by weight of cement in concrete mixing plan, were investigated....
Catodic Protection Design & Installation of Rebars in Reinforced Concrete by MMO Anodes
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor) ; Ghorbani, Mohammad (Supervisor)
Abstract
The cathodic protection system was employed for protection of the reinforced concrete of the foundations using the mixed metal oxide anodes embedded in concrete for current distribution. . In this system, after required measurements for zone design calculation of the surfaces current density, IR drop and the circuit’s resistance has been measured. After specifying the appropriate locations for the reference Electrodes (Ag/AgCl) in order for cathodic protection monitoring these three electrodes are installed in three protection zones. After design and supply of all the materials, the installation was started. The protection criterion of steel in concrete was studied and all the measured...
Gold and Gold-Nickel Pulse Electrodeposition
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor) ; Ghorbani, Mohammad (Supervisor)
Abstract
In recent years use of expensive metals plating has taken much interest from decorative state to industry trends. In this research the effect of pulse plating on the structure and properties of pure gold and gold-nickel has been studied.In case of pure gold pulse plating from cyanide bath, it was shown that current efficiency increased by increasing duty cycle up to 30% and decreased, afterwards. By increasing frequency from 1 to 150 Hz current efficiency decreased. By reducing the level of frequency, average grain size was increased, owing to the occurrence of recrystallization. An increase in the value of current density was also shown to be responsible for a reduction in current...
Investigation and Optimization of Ni-P-Zn Electroless Alloy Coatings
, M.Sc. Thesis Sharif University of Technology ; karam, SaeedAllah (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
An optimization condition for obtaining Ni-Zn-P electroless alloy coating has been developed. The sulphate bath with sodium hypophosphate as a reducer and sodium citrate and ammonium chloride as complexing agents were used. The effect of variation in the pH level , temperature , time of deposition and reactants concentration on stability of bath, coating composition, microstructure, microhardness and corrosion resistance of coatings was investigated. The composition of coatings was obtained by using the EDAX analysis. To investigate coating morphology, SEM images were taken and to study the corrosion behavior of coatings potentidynamic polarization, Electrochemical Impedance Spectroscopy...
Pulse Electrodeposition of Chromium Coating From Trivalent Bath and Studying it’s Properties
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
Trivalent chromium plating has been known as a very promising technology to replace hexavalent chromium which is so toxic. The coatings obtained from tivalent chromium baths have lower thickness and Hardness and higher corrosion rate in comparison with deposits obtained from hexavalent chromium baths.A few studies on pulse plating of trivalent chromium as an effective way to enhance the coating properties have been published.
In this research glycine was chosen as complexing agent.The results have shown that in pulse plating at 1 Hz, Duty cycle 50%, peak current density 0/2 A/Cm2 and after 30 minutes, thickness achieves 13 µm which is much greater in comparison with coatings obtained in...
In this research glycine was chosen as complexing agent.The results have shown that in pulse plating at 1 Hz, Duty cycle 50%, peak current density 0/2 A/Cm2 and after 30 minutes, thickness achieves 13 µm which is much greater in comparison with coatings obtained in...
Synthesis of Aligned Carbon Nanotubes and Their Modification with Noble Metallic Nanoparticles as Organic Analytes Biosensors
, Ph.D. Dissertation Sharif University of Technology ; Afshar, Abdollah (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
An efficient method has been developed to synthesize well-aligned multi-walled carbon nanotubes (MWCNTs) on a conductive Ta substrate by chemical vapor deposition (CVD). By varying CVD parameters, aligned CNTs (A-MWCNTs) with diameter between 20-100 nm and length of some micrometers with bamboo-like shapes were produced. Free-standing MWCNTs arrays were functionalized and purified through electrochemical oxidation. Then in order to improve the performance, facile template-free electrochemical routes were developed for the shape-selective synthesis of less-common Au nanostructures, including flower, sphere, dendrite, sheet and rod on A-CNTs at room temperature. The results showed that the...
An Investigation on the Pulse Electrodeposition of Ni-TiO2/TiO2 Multilayer Structures
, Ph.D. Dissertation Sharif University of Technology ; Dolati, Abolghasem (Supervisor) ; Ghorbani, Mohammad (Supervisor)
Abstract
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...
Characterization of Elecroless Ni-P-Al2O3-SiO2 Nano-composite Coating on Aluminium
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
In this study Ni-P-Al2O3-SiO2 nano composite coating developed on aluminium alloy 6061 using electroless method. Due to oxidation of aluminium, a double zincate pretreatment performed to obtain proper adhesion of coating on substrate. Effect of solution temperature and heat treatment on thickness and property of nano composite coating was studied. Furthermore, effect of concentration of nano particles in electroless solution on thickness, morphology, micro hardness, wear behavior, corrosion resistance and particle content in coating were investigated. Field emission scanning electron microscopy (FESEM, Hitachi S-4160) with energy dispersive spectroscopy (EDS) was used to evaluate morphology...
Fabrication of a Sensor, Based on TiO2 Nanotubes Modified with Metal Nanoparticles and Carbon and its Application for Detection of Dopamine in Presence of Uric Acid and Ascorbic Acid
, Ph.D. Dissertation Sharif University of Technology ; Askari, Masoud (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
The present work describes sensing application of modified TiO2 nanotubes towards detection of dopamine. The TiO2 nanotubes electrode was prepared using anodizing method at different conditions, among which NaF/ NaHSO4 solution and voltage of 15 V was chosen as the optimum condition. In order to improve the performance, surface modification with metal nanoparticles (Pd, Pt and Au) and carbon is required using “pulse electrodeposition” and “decomposition of polyethylene glycol at 600 °C” respectively. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. In this regard two type of electrodes were proposed: Pd-Pt-Au-TiO2 and C-Ni(Pt)-TiO2....
Electrophoretic Deposition of TiO2 Self-Cleaning Coatings
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
In this research, TiO2 nano-particles were electrophoretically deposited on the FTO glass to produce self-cleaning property. Two type of suspensions with different TiO2 nano-powders were used. Merck and fabricated by sol-gel route, TiO2 nano-powders were utilized in suspensions and Conductivity, pH and zeta potential of suspensions were determined. Electrophoretic deposition of two kind of suspensions was performed in different voltages of 10, 30 and 60V (for 10s) and room temperature. TiO2 coatings were sintered in 450oC for 1 hour. The phase transformation of TiO2 films were measured using XRD. Morphology, average particle size and thickness of TiO2 films were analyzed using FESEM...
Photoactive TiO2–SiO2 Thin Films on 316L Stainless Steel for Self-Cleaning Application, Tribological Properties and Corrosion Protection
, Ph.D. Dissertation Sharif University of Technology ; Afshar, Abdollah (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
In this study, TiO2-SiO2 nanocomposite films with different amount of SiO2 were prepared by sol-gel process and were coated onto stainless steel 316L. The effect of addition of various amounts of SiO2 in the precursor solution on the structure, morphology, photocatalysis, photo-generated hydrophilicity, self-cleaning property and mechanical properties of TiO2 thin films and corrosion behavior of AISI 316L stainless steel substrate, was investigated. For this purpose, X-ray diffraction, Fourier transform infrared spectroscopy, water contact angle measurements, UV spectroscopy, field-emission scanning electron microscopy, atomic force microscopy, depth-sensing indentation technique supporting...
Preparation and Characterization of ZrO2 Antistatic Coatings on Glass
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor) ; Afshar, Abdollah (Supervisor)
Abstract
In this study, the zirconia antistatic coating was synthesized by dip coating sol-gel route on glass substrate. The solution contains ZrCl4 as precursor and isopropanol as solvent to synthesize zirconium oxide. The effects of environmental humidity and solution concentration on the coating characterization were analyzed. MPTS and primer binder were added as binding agents in the solution to observe the effect of binding agents on the coating adhesion. Solution stability and antistatic coating characterization were analyzed by zita potential test, FTIR spectroscopy, EDX analysis, FESEM and AFM microscopy, pencil hardness test, thickness test, antidust ability and spectrophotometer. The...
Electrodeposition of Pt nanostructures and its Application as Glucose Sensor
, Ph.D. Dissertation Sharif University of Technology ; Dolati, Abolghasem (Supervisor) ; Ghorbani, Mohammad (Supervisor)
Abstract
The present work describes sensing application of modified Pt nanostructures towards detection of glucose. Modified Pt nanostructured electrodes were prepared using electrodeposition method such as chronoampermetry and potentiostatic pulse methods. The electrodeposition of Pt nanostructures was first studied by voltammetry and amperommetry techniques and then potentiostatic pulse method has been used to produce the alloyed structures of platinum. In this regard, the first electrode was proposed based on alloyed Pt/Ni nanowire arrays (NWAs) for the non-enzymatic detection of glucose. The Pt/Ni NWAs were prepared by pulse electrodeposition of Pt and Ni within a nano-pore polycarbonate (PC)...
Elecrodeposition of Copper- Diamond Nanocomposite Coating
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
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...
Copper-cobalt/Tungsten Carbide Nano-composite Coatings Deposited on Pure Copper Substrate by Electrochemical Deposition
, M.Sc. Thesis Sharif University of Technology ; Abachi, Parvin (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
In this research a copper- Tungsten carbided nanocomposite coating prepared by electrodeposition from a sulfate bath in order to increase the hardness and erosion resistance of cooper without loosing cooper's specific physical properties as like as electrical and thermal conductivity. Various parameters were evaluated for finding significant factors in electrodeposition of Cu-Co/WC composite. Current density and concentration of WC and SDS were selected as affective factors. The morphology and structure were characterized by XRD and SEM. The mechanical properties of the coatings, such as hardness, wear resistance and surface roughness were studied with Vickers hardness indentation; pin on...
Hydroxyapatite Coating on Nanotubes TiO2
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
There are many techniques that have been used to create hydroxyapatite nanoparticles coating on nanotubes. Electrophoretic deposition (EPD) is one of the methods that has advantages of short formation time, needs simple apparatus, little restriction of the shape of substrate, no requirement for binder burnout as the green coating contains few or no organics. In the research, first, titanium dioxide nanotubes were fabricated by anodic oxidation. Anodizing voltage effect on the morphology of nanotubes was evaluated. SEM images was shown that in the anodizing voltage 20V, nanotubes were the most regular. Then, Hydroxyapatite nanoparticles has been deposited onto nanotublar TiO2 by...