Loading...
Search for:
ghorbani--mohammad
0.137 seconds
Total 5268 records
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
In the preceding years, hydroxyapatite (HA)-based coatings and scaffolds have been known as the best biomaterials for dental and orthopedics applications. Biocompatible and bioactive hydroxyapatite-based Coatings on metallic implants is one of the best methods for reaching both suitable mechanical properties and appropriate bioactivity, leading to better osseointegration and osteoblast proliferation. The ultimate goal of this project is characterization as well as mechanical and electrochemical behavior investigation of Hydroxyapatite- Chitosan nanocomposite coating by electrophoretic deposition (EPD) method on Plasma Electrolyte Oxidation (PEO) treated titanium substrates and Magnesium (Mg)...
Non-Scratch, Antibacterial And Self-cleaning SiO2/TiO2 Nano Composite Coating on Surgical Tools By Sol-Gel
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
In this study TiO2/SiO2 thin films were prepared by sol-gel method from Tetra isopropylortho Titanate(TIPT) as the principle of TiO2 material with Tera ethoxysilane(TEOS) as the principle of SiO2 material to achieve high scratch-resistant , antibacterial and self-cleaning surface area under the effect of various percentage of SiO2 . Film deposition was carried out using a dip-coating technique and heat-treatment was used at 700ºC to achieve crystalline of films with excellent adherence the of substrate.
The surface morphology of the films has been observed by Scanning Electron Microscope (SEM) and the tribological properties of the surface were investigated by Atomic Force Microscope...
The surface morphology of the films has been observed by Scanning Electron Microscope (SEM) and the tribological properties of the surface were investigated by Atomic Force Microscope...
Electrochemical Behaviors of RuO2-TiO2 Mixed Metal Oxide Coated on Titanium Anodes in Chlor-Alkali Electrolysis
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Titanium anodes activated by noble metal oxides under the trade name of dimensionally stable anodes (DSAs) are widely used in the electrolytic industry, particularly in chlor – alkali electrolysis. Over 20 years of use, the fundamental aspects of their long – lasting performance are not fully understand and the corrosion mechanisms are still the subject of many investigations. RuO2 – TiO2 coatings on titanium substrate, due to proper electrochemical characteristics and good corrosion resistance, is most applicable as an anode in chlor – alkali systems. In the present investigation, the first layer of Pt – Ir coating is applied via electrodeposition method on the pretreated titanium substrate...
Electroplating of Bronze-Graphite-SiC Composite Coating
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Composite coatings including self-lubricant particles such as graphite, MoS2, Al2O3 and SiC are extensively used to decrease the coefficient of friction of tribo-surfaces. Adding lubricant particles to an appropriate metallic matrix like copper, nickel, lead and their alloys is a suitable option in severe condition –for instance high temperature and low pressure- which liquid lubricants will be failed. Bronze can give various properties such as wear resistance, corrosion and oxidation protection, However cyanide solutions for electroplating process have environmentally limited for plating of Cu-Sn. In this research, a chloride electrolyte for bronze electroplating was developed and effect of...
The Corrosion Behavior of Zinc and SiO2 Composite Coating
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Main aim of this work was to obtain the harder zinc coating and increasing the anti corrosive properties by mean of adding SiO2 particles by electrophoretic method.
The coating was applied on the substrate surface by mean of electro co-deposition technique in three different electrolytes ethanol, methanol and water. The morphology of the coating in each electrolyte studied by scanning electron microscope (SEM).For the Zn/SiO2 coatings achieved in ethanol solvent the polarization and EIS tests was took place and found that for the Zn/SiO2 coating contain less than 10% SiO2 the corrosion rate decreased but for the coatings contains more than 10% SiO2 the paradox occurred because of the...
The coating was applied on the substrate surface by mean of electro co-deposition technique in three different electrolytes ethanol, methanol and water. The morphology of the coating in each electrolyte studied by scanning electron microscope (SEM).For the Zn/SiO2 coatings achieved in ethanol solvent the polarization and EIS tests was took place and found that for the Zn/SiO2 coating contain less than 10% SiO2 the corrosion rate decreased but for the coatings contains more than 10% SiO2 the paradox occurred because of the...
Electrochemical Deposition of Composite Coatings of Nickel - Silicon Carbide Under Pulsed Current Using a Rotating Disk Electrode
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Ni-SiC composite coatings are widely used in industry (equipment high wear resistance coatings, corrosion resistant coatings, ship and boiler coatings, . . . ). Its unique properties in high wear resistance, corrosion resistance and tribological properties, researchers tend to investigate this coating. This study covers Ni-SiC composite coating under pulsed current using a rotating disk electrode to achieve optimal conditions in synthsis process, increaseing hardness and resistance to corrosion in coatings.waats' bath established for electrodeposition in this research. Bath parameters, current parameters and hydrodynamic of solution is examined. Changing of current type from direct current...
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)...
The Effect of Porosity on Photocatalytic Properties of TiO2 Nanocoating Fabricated By Sol-Gel
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
This thesis is concerned with the synthesis and characterization of high porous Ti based on thin films and the effect of polymer agents on their photocatalytic properties. Ti films can demonstrate different properties like self -cleaning and treatment of broad range of aqueous pollutants when it is exposed to light of wavelength less than 400 nm. This is due to photocatalytic reaction occurring on film surface which results in film superhydrophilicity and the active oxygen species production. This active sites and radicals will cause oxidize organic pollutants and microbe adherent to the material surface.
In this study Ti thin films have been prepared by the sol-gel method from...
In this study Ti thin films have been prepared by the sol-gel method from...
Physicochemical and Photocatalytic Properties of Fe, Gd and P Doped TiO2 Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Improving the photocatalytic activity of titania nanoparticles and Cognition the mechanisms governing this property, has received more attention in the recent few years. One of the main strategies for improving the photocatalytic activity and modifying the bandgap structure of titania nanoparticles, is incorporation different metallic and nonmetallic ions in the titania lattice. In this study, 1%Fe, 1%Gd and 2%P (molar ratio) doped titania nanoparticles were successfully prepared by a modified sol-gel method in room temperature. The products were characterized with various spectroscopic and analytical techniques to determine their structural, morphological, physicochemical and...
An Investigation on Photocatalytic Properties of Sol-Gel Produced TiO2-SiO2-Ni Nanocomposite Coatings
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Titania is one of the photocatalytic materials , but low quantum yield and relatively high band gap of TiO2 limited its applications.There are several ways to improve the photocatalytic properties of this material relied on narrowing the band gap,by doping TiO2 with other metals and oxides or increasing its specific surface area.In this work ,TiO2-SiO2-Ni coating have been made by sol-gel process and deposited on quartz substrate by using of dip-coating method .Effect of increasing Nickel content in nanocomposite and primary sol on crystalline structure,morphol ogy, photocatalytic properties and specific surface area have been investigated by means of X-Ray diffraction method, FT-IR, SEM,...
Synthesis and Antibacterial Activity of TiO2/ZnO Nanocomposite via Sol-Gel Method
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
The synthesis and usage of TiO2/ZnO nanocomposite thin film in antibacterial activity against E-coli were experimented through a systematic research. TiO2/ZnO nanocomposite films can demonstrate different properties like gas sensing, self cleaning and treatment of the broad range of aqueous pollutants when it is exposed to light with wavelengths less than 400 nm. This phenomenon happens because of the photocatalytic reactions in the nanocomposite thin film which cause active species production on the surface of the thin film. The nanocomposite synthesis was based on sol-gel process in atmospheric pressure. In this study titanium dioxide is prepared by sol gel method from titanium...
Synthesis of Doped Titania Nanotube Arrays by Anodizing of Titanium and Surveying of their band Gap
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
In recent decade, photocatalystic properties of titania nanotube and its mechanisms has been considered greatly in many researches. One of the major ways to increase photocatalystic properties and extending the usage of TNTs is doping them with various elements and modifying their band structure. In present research doped TNTs were prepared by doping of Molybdenum, Nitrogen, and Carbon elements by anodizing method in about of 35 degrees of centigrade and constant voltage of 20V on the surface of titanium sheet. Structural and photocatalystic properties of as-prepared TNTs were studied using field emission scanning electron microscope (FESEM), x-ray diffraction (XRD), energy dispersive...
Preparation and Characterization of Nanostructural Ternary Mixed Oxide Containing Ti/Ru/Ir on Titanium by Sol-gel Process for MMO Electrode
, Ph.D. Dissertation Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
In this study, ternary metal oxide coating consisting of Ti, Ru, Ir were prepared by sol-gel method. In order to achieve optimal conditions, the effect of number of layers, temperature and velocity of the heat treatment, the amount of ruthenium and iridium, polymeric additive on the coating and also, comparisons of binary and ternary oxide coatings were studied. The corrosion behavior was examined by anodic polarization and cyclic voltammetry tests and accelerated stability test (AST), the morphology of coatings was studied by field emission scanning electron microscopy (FESEM), phase and elemental analysis was performed using X-ray diffraction (XRD) and energy dispersive spectroscopy...
plasma Electrolytic Oxidation of AZ31 in Silicate and Phosphate Electrolyte and Study of Corrosion Behavior
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
In recent years, magnesium and its alloys have been considered as biodegradable implants, but they corrode in the body before natural process of damaged organs recovery is completed. In this investigation PEO operation was used for corrosion control and effect of different parameter such as number of operation steps, electrolyte type, time and operation voltage on coating properties was studied. Scanning electron microscopy was used for investigating of morphology of coats and to determine chemical composition and phase of coats EDS analysis and X-ray diffraction were used. The corrosion resistance of samples were evaluated by potentiodynamic polarization and electrochemical impedance (EIS)...
Electrochemical and Photocatalytic Behaviour of V&S Doped Titania Produced with Plasma Electrolytic Oxidation
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Plasma Electrolytic Oxidation is a new and promising method for synthesis of oxide layers and coatings on light metals such as titanium and aluminum. This method is a fast, easy and economicalway to produce TiO2 layers on Ti substrate. Photocatalytic properties of TiO2 can be improved with doping of other elements such as metals and non-metals by expanding its band gap which is in UV area of light spectrum in to visible area.Photocatalytic properties of TiO2 is also dependent on surface area and grain size, oxide layers which has been produced with PEO process has a high surface area due to its porosity. Voltage, electrolyte and additives concentration are among parameters which can affect...
Deposition of TiO2/SiO2 Nanocomposite on Cotton Textile by Sol- Gel Method
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
The synthesis and usage of nanoscaled TiO2 accompanied by the photocatalytic activity were experimented through a systematic research. The synthesis was based on the sol-gel method at low temperatures and atmospheric pressure. In recent years, many endeavors have been made so as to enhance the efficiency of TiO2 photocatalytic activity. The studies show that the inclusion of SiO2 into the TiO2 can give rise to the photocatalytic activity relevant to the derived composite Nanoparticles with regard to the pure TiO2. In this study, the production of TiO2-SiO2 Nanocomposite layers was proceeded via the sol method and the effect of SiO2 increasing and its amount in the primary solution on the...
H2S Gas Sensing Characterization of Nano-Structured SnO2-CuO Multilayer Sensor
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Co-Advisor)
Abstract
Hydrogen sulfide, H2S, is a toxic gas and has detrimental effects on human health and the oil and gas industry. Therefore, its identification is very important. According to the devastating effects of this gas, then, the general mechanisms have been studied for gas detection. In addition, by highlighting the benefits of the multilayer nanostructure electrochemical sensors, an applicable and efficient method for the industrial production of these sensors has been investigated. In this regard, the sol-gel method is used to prepare the SnO2-CuO multilayer thin film and the advantages of this method was compared to PVD method. Also sensor properties of both deposition methods have been...
Formation of Plasma Electrolytic Oxidation Coating on Mg-Ti Coupl Joint with Friction stir Welding Process and Evaluation its Properties
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Plasma electrolytic oxidation is the novel surface engineering technology that used as the low cost and eco-friendly method for improvement of corrosion resistance and wear resistance of Mg and Ti alloys. The aim of this investigation is firstly joint the Ti and Mg, then optimization of coating process condition of Ti-Mg couple for achieve the best corrosion and wear resistance of coating. For this purpose, initially Ti and Mg were joint together by friction stir welding treatment and then the effect of coating variable such as type of electrolyte, coating voltage, coating time and the concentration of the bath constitute, on the coating properties were investigated, and then the effect of...
AC Anodizing of Pure Titanium Grade 2 with HA Nano Particle
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
In this study, biocompatible ceramic coating, containing hydroxyapatite particles (HA), was successfully created by AC anodizing, on the surface of commercially pure titanium grades 2. Coating process basically consisted of three methods. In Method 1, samples were anodized in a salty electrolyte containing calcium – phosphate base and in method 2 samples were anodized as initial process, following cathodic polarisation deposition of HA particles. Finally in method 3, samples were anodized in an electrolyte containing of HA particles suspension.Parameters such as current density and time of anodizing process, in first procedure, and time of cathodic deposition process in second procedure, and...
Preparation of Composite Coating with ZrO2 Nanoparticles on Mg alloy using AC Plasma Electrolyte Oxidation
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Plasma electrolytic oxidation (PEO) was implemented to produce a ceramic coating on AZ31 magnesium alloy, using an alternate power source (AC), in a silicate based electrolyte containing zirconia nanoparticles in different concentrations. Prior to adding nanoparticles to electrolyte, working parameters such as current density, frequency and coating duration were examined and studied concerning the equipment and coating conditions. And after reaching the optimized condition, ZrO2 nanoparticles were added to the electrolyte to create composite coatings. To examine the properties of the coatings before and after the creation of composite PEO coatings, scanning electron microscopy (SEM) was used...