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The Structure and Corrosion Behavior of Synthesized Zn-SiO2 Nano-composite Coating by Sol-Gel Method
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Zinc–silicanano-composite coatings were produced by successive dip coatand sintering procedure from different sol-gel solutions. The surface and cross-sectional morphologies of Zn-SiO2 nano-particles (NPs) were examined using field emission scanning electron microscopy (FE-SEM). Corrosion resistance evaluated by means of polarization and electrochemical impedance spectroscopy showed that even thin films of Zn-SiO2 in orders of 200 nm can have corrosion rates as low as conventional hot dip galvanized steels. Multi-layers coatings have been studied and showed that 10 layers coating with the thickness of 2m has the lowest corrosion rate with the passive region in anodic branch. Corrosion...
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
Abstract
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...
Tribological and Corrosion Properties of Ni-SiC (FGM) Coatings
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Ni-SiC nanocomposite coatings are considered as corrosion resistant coatings with better tribological properties. In order to get superior properties, the amount of added particles should be increased. But high concentration of particles has some drawbacks such as low adhesion to substrate, probability of cracking in coating due to heat expansion coefficient difference between substrate and coating and also embrittlement of coating and low elasticity. In this study, the possibility of producing Ni-SiC nanocomposite coatings with FGM structure was investigated. SiC particles concentration was 5 to 80 g/l and the current density was between 3 to 5 A/dm¬2. The pH of bath and temperature was...
Production of Cr-Al2O3 Nano-Composite Coatings by Electrodeposition
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhad, Khatiboleslam (Supervisor)
Abstract
Electroplating is an appropriate method for co-deposition of metallic, non-metallic and polymeric fine particles onto a metal matrix for production of functional coatings. In this study, chromium and Cr–Al2O3 composite coatings are electrodeposited from trivalent chromium bath by using DC and square pulse current. Dependence of the amount of Al2O3 nano-particles trapped into the coatings on the Al2O3 bath concentration, average current density, particle size, agitation rate and type of the current is investigated. These parameters are optimized for the highest co-deposition amount of the Al2O3 onto chromium layer. Optimum values are 20g/l Al2O3, 200 rpm stirring rate and 25A/dm2 current...
Investigation on Synthesis and Properties of TiO2-CNT Nanocomposites Coating on Al Substrate
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Sadeghian, Zahra (Supervisor)
Abstract
The aim of this project is investigation on synthesis and characterization of the TiO2-CNT nanocomposite films on aluminum substrate by sol-gel dip coating method. The pure TiO2 and TiO2-CNT nanocomposite layers were coated on aluminum substrate and heat treated in 400 C. In this work Ti-tetra isopropxide and different amounts of CNTs (5,10,15 %wt), were used for obtain the composites. The coatings were characterized by X-Ray diffraction (XRD) and the crystallite size of TiO2 was calculated by Scherrer formula. The corrosion properties of coating were examined by polarization test, and corrosion resistance of pure TiO2 was compared with TiO2-CNT coatings, and It showed that the composite...
Electrophoretic Deposition of Chitosan- Hydroxyapatite- Multiwalled Carbon Nanotube Composite Coatings
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
At the first stage, chitosan-hydroxyapatite-multiwalled carbon nanotube (CH-HA-MWCNT) composite coatings were synthesized by electrophoretic deposition technique (EPD) on Ti6Al4V and 316L stainless steel substrates at different levels of pH and characterized by X-ray diffraction (XRD), Raman spectroscopy, FTIR and field emission scanning electron microscopy (FESEM). A smooth distribution of HA and MWCNT particles in a chitosan matrix with strong interfacial bonding was obtained. At the second stage, effect of pH and MWCNT content of the suspension on corrosion behavior and mechanism of deposition were studied. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)...
Synthesis and Electrochemical Evaluation of Graphene-Ni/Cu/Zn Nanocomposite Coating Modified by Pt/Ru Nanoparticles
, Ph.D. Dissertation Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
In this research,Graphene Oxide nanoplatelets (GO) were synthesized by chemically modified Hummer's method.After the GO nanosheets electrochemically reduced to graphene, nanoparticles imposed to this thin film.This optimized nanostructure coating was utilized for investigating the Hydrogen Evolution Reaction (HER) over the copper substrate. In order to optimize the kinetic of electrodeposition and reduction, diverse electrochemical approaches such as cyclic voltammetry, chronoamperometic and potentiometric as well as pulse electrodeposition methods were employed. Electrochemical procedures were aligned by Design of Experiment (DOE) ...
Electrodeposition of Ni-SiC Nanocomposite Coatings
, Ph.D. Dissertation Sharif University of Technology ; Dolati, Abolghasem (Supervisor) ; Ghorbani, Mohammad (Co-Advisor)
Abstract
In this project Ni-SiC nanocomposite coatings were electrodeposited using Watts nickel bath with addition of SiC particles to the bath. Optimization of Ni-SiC electrodeposition parameters was done using Response Surface Methodology (RSM). At specific conditions, 67 Vol% of 10nm SiC is incorporated in nickel electrodeposits which is unique and not yet reported. Study nanomechanical properties of these coatings using Nanoindentation method, it was realized that the dislocation density is increased as force increasing which is in agreement with increasing intensity of (220) and (200) reflections and intensity attenuation of (111) reflection. Nanoscratch tests show that these...
Preparation and Characterization of Inhibitor Loaded Nanodiamond for Anticorrosion Coating
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Pirhadi, Nahid (Co-Supervisor)
Abstract
In recent years, nanodiamond (ND) has been used as reinforcement in polymeric nanocomposites in order to improve mechanical properties, thermal conductivity, etc. The surface of nanodiamond has several functional groups which make it appropriate adsorbent. In this study, nanodiamond was modified with dodecylamine corrosion inhibitor and was utilized (1wt %) in epoxy based nanocomposite. Fourier transform infrared spectroscopy (FTIR) analysis was used to confirm the surface modification of Nanodiamond. In order to estimate the loading amount of corrosion inhibitor, thermogravimetric analysis was investigated. FE-SEM analysis demonstrated nanoparticle dispersibility in epoxy matrix. Regarding...
Production and Properties of Reduced Graphene Oxide- Zinc Nanocomposite Coating on Steel
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
In this project, graphene oxide was produced by chemical method (modified hummers method) because of simplicity and reproductiblity in the manufacuring process. Zinc nanoparticles were produced from pure zinc anode in the graphene oxide solution (anodic dissolution). Nanocomposite coating of reduced graphene oxide – zinc was created by electrochemical reduction with voltage pulse. Optimization of corrosion current density of the coating was done by design of experiments software (central composite design). To achieve this goal, several parameters such as cycles of zinc dissolution, frequency, duty cycle, total time of coating and applied voltage were examined. Using analysis of variance...
Pulse Electrodeposition of Ni-Fe Composite Coating with Nano-TiO2 Particles and its Properties
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
In this study, pulse electrodeposition of Ni-Fe composite coating with and without nano-TiO2 particle in sulphate bath was performed and effects of peak current density, frequency, duty cycle and type of current on their properties was investigated. Also effect of pulse parameters on the composition and amount of particles in coatings was determined. Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) analysis was used to study the morphplogy and structure of coatings. The chemical composition of deposits was examined by Energy Dispersive X-ray Spectroscopy (EDS) attached with Scanning Electron Microscopy and Atomic Adsorption...
Electrophoretic Deposition of Ni/SiO2 Nanocomposite Coating: Fabrication Process and Tribological and Corrosion Properties
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Ni/SiO2 nanoparticle composite coatings were prepared by electrophoretic deposition (EPD) and their hardness, wear and corrosion resistance were examined. Additionally, the morphology of the coatings was observed. In the first phase, the feasibility of coating with Scanning Electron Microscopy (SEM) as well as X-ray diffraction (XRD) and Energy Dispersive Spectra (EDS) techniques was evaluated. After finding the effect of concentration of nanoparticles on coating characteristics and the results of using SEM, optimum conditions for uniform coating, acceptable adhesion at 20V and concentrations of 10 g/L for Ni, 1.2 g/L for SiO2, and choosing NiCl2 as additive with a concentration of 0.2 g/L...
In-Situ Synthesis of Zif-8 Nanocomposite Coating on Carbon Steel and Investigating the Effect of Adding Mbt on Corrosion Behavior and Sic Nanoparticles on Mechanical Properties
, M.Sc. Thesis Sharif University of Technology ; Abachi, Parvin (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
Nowadays, metal-organic frameworks have received a lot of attention due to their properties and characteristics such as controllable structure, high specific surface area and the tunable porosity size and have found many applications. One group of metal-organic frameworks are zeolitic imidazolate frameworks which ZIF-8 is a member of this family, and many studies have been conducted on it. In the present study, ZIF-8 nanocomposite coating was applied to the plain carbon steel substrate by synthesis at room temperature and immersion method, and its corrosion behavior and mechanical properties were investigated. The effect of Mercaptobenzothiazole (MBT) inhibitor on corrosion behavior and...
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
2012
Abstract
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....
Production of Zn-Tio2 Nanocomposite Coating by Electrochemical Method and Investigation of its Properties
,
M.Sc. Thesis
Sharif University of Technology
;
Ghorbani, Mohammad
(Supervisor)
;
Afshar, Abdollah
(Supervisor)
Abstract
Pure zinc coating and Zn-TiO2 composite coating were deposited from two methods: Direct and Pulse Current from a sulphate bath. D.C. section, current density and particle concentration in electrolyte were investigated. Moreover in Pulse section, frequency, duty cycle and maximum current density were investigated as parameters. Morphological properties of these coatings were investigated by FE-SEM and corrosion behavior by potentiodynamic polarization in 1M NaCl. In D.C. section, in investigation of the effect of current density, an optimum was observed in case of obtaining the highest amount of deposited particles at 0.1 A/cm2 and amount of 2.93%. This amount is the highest one in D.C....
Investigation Ni-P-Al2O3-SiO2 Nano Composite Coating on Aluminum by Electroless
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
Electroless coating is a chemical reduction process which depends on the catalytic reduction. In this study, the influences of different concentrations, stirring rate, pH and heat treatment of Al2O3 and SiO2 Nano sized particles in the bath on deposition rate, hardness, wear resistant, surface morphology and corrosion behavior of the Ni-P-Al2O3-SiO2 composite coatings have been investigated. The microstructure was investigated by field emission scanning electron microscopy (FESEM) and among the nanoparticles SiO2 and Al2O3 have drawn attention due to their high hardness, availability, particles distribution and reduced cost. The amount of Al2O3 and SiO2 was examined by Energy Dispersive...
Produce of Nano composite Antibacterial Coating of PDMS+TiO2+ Ag3PO4 on 316SS Using Sol-Gel Methods and its Properties
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdullah (Supervisor)
Abstract
The aim of this research is to create coatings with antibacterial and superhydrophobic properties. To evaluate this, the sourness angle test, bacterial culture and halo diameter test have been used. The results show that 316L stainless steel containing PDMS+TiO2+7%Ag3PO4 coating, which is applied by immersion method on the substrate, has a water contact angle of 152 degrees, the number of bacteria cfu.cm2 is 44000 and the halo diameter is 24 mm. which has the best performance among other examples. In order to increase the adhesion of coatings on 316L stainless steel, first heat treatment was performed and then the samples were placed in H2SO4:H2O2 solution for 1 hour to form its OH- groups...
Produce of Antibacterial Composite Coating of PTFE+Ag+TiO2 On 316SS and Study Its Properties
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
This research investigated the corrosion and antibacterial properties of PTFE+TiO2/Ag coating and its adhesion to 316L stainless steel. To increase adhesion, polydopamine coating was created as an intermediate layer by chemical deposition method on stainless steel, then PTFE + TiO2 coating was created on the sample by immersion method, and then silver nanoparticles were applied as the third layer by chemical deposition method. According to the polarization curves, the most corrosion-resistant coatings with corrosion current density of 3.34×10-5 and 3.25×10-4 μA are coatings PTFE+TiO2 and PTFE/PTFE+TiO2/Ag respectively. In terms of antibacterial activity, according to the non-growth halo...
Preparation and corrosion resistance of pulse electrodeposited Zn and Zn-SiC nanocomposite coatings
, Article Applied Surface Science ; Vol. 300 , May , 2014 , pp. 1-7 ; ISSN: 01694332 ; Mozafari, A ; Omidvar, H ; Javanbakht, M ; Sharif University of Technology
Abstract
Pure Zn and Zn matrix composite coatings containing nano-sized SiC particles with an average size of 50 nm were prepared from the zinc sulfate bath. The effects of the pulse frequency, maximum current density and duty cycle on the amount of particles embedded were examined. Electron microscopic studies revealed that the coating morphology was modified by the presence of SiC nanoparticles. In the presence of SiC nanoparticles deposit grows in outgrowth mode resulting in a very rough and porous microstructure. However, at very low and very high duty cycles a smooth and pore free microstructure was obtained. Corrosion resistance properties of the coatings were studied using potentiodynamic...
Microstructure-corrosion resistance relationship of Direct and Pulse Current electrodeposited Zn-TiO2 nanocomposite coatings
, Article Ceramics International ; Vol. 41, issue. 1 , 2014 , pp. 217-224 ; ISSN: 02728842 ; Ghorbani, M ; Afshar, A ; Sharif University of Technology
Abstract
Zinc-TiO2 nano-composite coatings were synthesized by Direct Current (DC) and Pulse Current (PC) electrodeposition techniques. The effects of the plating parameters on the microstructure, codeposition percentage of TiO2 and corrosion behavior were investigated. The coatings morphology presents hexagonal grains perpendicularly oriented to the surface. Under DC conditions, TiO2 content of the coatings decreased with increasing TiO2 concentration of the electrolyte. Increasing applied current and TiO2 concentration in the bath leads to a fine microstructure with corrosion currents as low as 2.7 μA/cm2. Under PC conditions, incorporation rate of nanoparticles tends to increase with increasing...