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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...
Investigation of Vanadium Dopant and SiO2 Prelayer on the Self-Cleaning Property of TiO2 Coatings by Sol-Gel Dip Coating Method
, M.Sc. Thesis Sharif University of Technology ; Faghihi Sani, Mohammad Ali (Supervisor)
Abstract
Because of limitation of titania coating that can act as self-cleaning surface under UV light irradiation, introduction of transition metal ions into titania lattice can decrease band gap energy of titania in order to activate the coating under visible light irradiation. In this research, by using vanadium element and silica prelayer, a titania coating was deposited on the soda-lime glass substarte to produce self-cleaning surface. The scope of coating was to increase the photocatalytic activity and hydrophilicity of vanadium doped titania coating on the soda-lime glass and silica coated glass by sol-gel dip coating method. XRD and FTIR analysis were done on the powders with different...
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)...
Investigating Bio-Capability of HA-ZrO2-TiO2 Nano-Composite Coating by EPD on St. St 316 in Physiologic Solution
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
Metallic implants are useful in dental and orthopedic applications. Bio coating is necessary to improve bio-compatibility and bio-activation of metallic implants. For this goal, HA is the most important material. In this research, the goal is to improve bio-compatibility of St. St 316 by coating HA, HA-ZrO2, HA-TiO2, HA-ZrO2-TiO2 using combination of electrodeposition and electrophoretic methods. To form HA, calcium and phosphor salt solution was used then ZrO2- TiO2 nanoparticles was added to solution. In order to analyst the coatings different tests were done. Thickness analysis, XRD, FT-IR, FE-SEM and EDS, bonding Strength, Polarization test, bio-compatibility and surface roughness...
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...
Synthesis of Tin and Ti2n Nanostructured Coatings on Ti alloys Using Magnetron Sputtering System And Comparison of Their Biocompatibility Properties
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Khamse, Sara (Supervisor)
Abstract
Considering the importance of biocompatibility of implantable prothesis’, metallic alloys have weaker corrosion resistance than ceramics. In order to extend usage of nanomaterials to improve the bio-properties of materials, Nano-structured ceramic coatings are being suggested to improve corrosion resistance and biocompatibility of prosthesis. Meanwhile, very good properties of TiN, such as corrosion resistance and mechanical properties as a thin film coating are undeniable. In this study, TiN and Ti2N thin film were deposited on Ti-based substrate, using PVD and Magnetron sputtering at different argon to nitrogen ratio. The crystal structure of the films was examined using Grazing XRD...
Synthesis of Anti-reflection and Self-cleaning Coating on Glass Substrate Using Sol-gel Method
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
Using of solar spectrum because of its potential for producing green energy is the topic of interest in Current decade. The goal of current research is increment of efficiency by using of a single layer and double layer semiconductor TiO2 – ZnO coating that has been synthesized by sol-gel process, which have anti-reflation and self-cleaning properties that in short time and long time for durability of solar systems can be useful. In first step of this research the single layer TiO2 (by 85nm thickness, measured by FE-SEM) and ZnO (by 65nm thickness) coating with different concentrations of pore forming agents ( plironic f127 for TiO2 and CTAB for ZnO) in coating sol examined and observed...
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...
Electrodeposition of Ag-Pd Alloy for Enhancing Corrosion Resistance
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
Silver is a resistant metal against the oxidation under normal atmospheric conditions, but it reacts readily with sulfur bearing species in the environment and corrodes. Alloying silver with more noble elements, such as Palladium, is a promising approach for increasing corrosion resistance against the sulfur pollutants. The purpose of this research is to develop a plating bath for deposition of Silver-Palladium alloy with acceptable appearance and higher corrosion resistance than pure silver. For this purpose, a bath based on thiosulfate complexing agent was investigated. In this solution, with a bath containing 10 mM of each cation, deposits with palladium content of 6, 11 and 14 % were...
Synthesis and Characterization of Anticorrosive Hybrid Epoxy Coating based on Polyaniline/Nanodiamond Nanostructures
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Pirhady, Nahid (Co-Advisor)
Abstract
One of the ways that corrosion control is presented is the use of coatings that have good properties such as high adhesion, impact resistance, ultraviolet radiation, and so on. They also have other unique properties like anti-corrosion property. To achieve coatings with these advanced properties, they use special properties of nanocomposites. Nanocomposites can add or improve one or more properties to coating properties.In the present study, we tried to first synthesize NanoDiamond/Polyaniline hybrid nanoparticles in different percentages and then use this hybrid in epoxy ester coating. To characterize this hybrid, various analyzes such as FE-SEM, TEM, FT-IR, UV-Visible, TGA and XRD were...
Effect of TiO2 Coating on Efficiency of Black Electroless Ni-P Solar Absorber
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor) ; Afshar, Abdollah (Supervisor)
Abstract
In this thesis Blackening of electroless nickel-phosphorous coating and the effect of TiO2 anti-reflection coating on optical properties of coating was investigated. In the first step, electroless nickel coatings with different amounts of phosphorous on 1050 aluminium substrate deposited. In second step, blackening of coatings by chemical and electroche-mical methods have studied and in final step, effect of TiO2 antireflection coatings with different amount of Pluronic F127 on the optimum black surface and properties of coating investigated. Chemical blackening performed in nitric acid and effect of acid concenteration, Blackening time and temperature studied. optimized condition was...
YSZ Coating on Ferritic Stainless Steel Interconnect through Sol-Gel Method and Studying its Reaction with Glass Sealant in SOFC
, M.Sc. Thesis Sharif University of Technology ; Faghihi Sani, Mohammad Ali (Supervisor) ; Nemati, Ali (Supervisor)
Abstract
Solid oxide fuel cells are used to convert solid-state energy to direct electrical current by electrochemistry mixing a gas fuel and an oxidant in an oxide electrolyte. One of the most interesting aspects of this field for the researchers is the reaction between the metal interconnect and the glass sealant. In the current research, deposition of the YSZ coating onto the metal interconnect in order to impede the reaction with glass sealant and prohibition of its oxidation in oxidizing/reducing environment in high temperature, was mainly investigated. Effect of applying YSZ Thin layer in the intersection of Crofer steel and glass sealant on strength and chemical durability of these two...
Evaluation of Shear Stress at the Interface of Asphalt Layers Using Finite Element Analysis
, M.Sc. Thesis Sharif University of Technology ; Tabatabaee, Nader (Supervisor)
Abstract
Tack coat is a layer of asphaltic materials, which is used for binding the surface layer to the current asphalt layer. The appropriate interlayer bonding condition will help different layers form a monolithic structure to resist traffic. The lack of proper interlayer bonding result in slippage between pavement layers, decrease the capability for transferring the load to the underlying layers, rutting, crescent cracking and decreasing the life of the Overlay. This study intends to model a pavement system in three dimensions with ABAQUS software in order to evaluate the amount of shear stress at the interface of asphalt layers. In order to prove the validity of the model, the results of the...
Corrosion Protection of Aluminium by Smart Coatings Containing Layered Double Hydroxide (LDH) Nanocontainers
, Ph.D. Dissertation Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
Smart coatings which prevent corrosion by several mechanisms recently have been carefully planned. One of these mechanisms is the use of ion exchangers like Layered Double Hydroxide (LDH) in the coating network. In this study, the LDH containing a kind of green inhibitor (sodium molybdate) was synthesized and utilized in a Poly-Vinyl Alcohol (PVA) base coating applied on the aluminium (5054 series) surface. After evaluating the LDH performance, the inhibitor release from the LDH crystals was examined by changing significant parameters like MII/MIII (the molar ratio of divalent ions into trivalent ions), pH, aging time and temperature. Considering the LDH morphology or the thickness of the...
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...
Numerical Study on the Post-earthquake Fire Behavior of Intermediate Steel Moment Frames
, M.Sc. Thesis Sharif University of Technology ; Kazemi, Mohammad Taghi (Supervisor)
Abstract
Nowadays, proper design and retrofitting of structures against natural and manmade disasters, is among the main concerns of researchers and designers in order to reduce financial and human costs. Extensive research has been carried out on the structures resistance against earthquake up to now. Although, the vast amount of research has resulted various regulations and guidelines, there is still a long way ahead to achieve the desirable results. Due to high sensitivity of the steel to temperature variations, fire exposure is more destructive for steel structures compared with the concrete ones. The performance of an intermediate three-storey steel moment frame with 4 spans was studied in this...
Finite Element Formulation for Thermo-elastic Analysis of Functionally Graded Coating on Axisymmetric Shell Structures
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kordkheili, Ali (Supervisor) ; Zabihollah, Abolghasem (Co-Advisor)
Abstract
In this paper, a finite element formulation is presented to study the thermoelastic behavior of Functionally Graded (FG) axisymmetric coating in shell structures. The power law distribution model is assumed for the composition of the constituent materials in thickness direction. The Plasma Spray with multi steps coating method is considered for coating method. The procedure adopted to derive the finite element formulation contains the analytical through-the-thickness integration inherently. So the explicit through-the-thickness integration becomes possible after defining a two-noded, three parameters degenerated axisymmetric FG element. The nonlinear heat transfer equation is used for...
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...
Synthesis of Antibacterial Hydroxyapatite/Titania-Silver Coating on Titanium Substrate Using Sol-Gel Method
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
With the increase in the average age of the world's population, osteoporosis is a worldwide incidence. This disease, along with natural disasters, are important factors in the occurrence of fractures in various bones of the body. One of the methods for solving this problem and replacing with broken body bones is the use of metal implants with hydroxyapatite-based coatings. One of the common problems with using implants in the body is the infection in the adjacent parts of the implant. To overcome this problem, several studies have been carried out on the use of hydroxyapatite coatings with metal ions or antibacterial oxide compounds. In the present study, the influence of factors such as the...
Study on the Properties of the Cationic Antistatic Polyurethane-based Coating
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
In this study, cationic polyurethane resin was synthesized by use of the reflux technique under N2 atmosphere. At first TDI was reacted with GMS to form prepolymer with terminal –NCO, also DBTDL was used as catalyst. This prepolymer was then reacted for chain-lengthening with N-methyl diethanolamine compound containing tertiary nitrogen atoms. The chain-lengthened product was then converted into an ammonium compound or cationic compound, by reacting with HCl as reactive hydrogen containing compound. The structure of product was studied by FT-IR spectroscopy. Then the cationic product was used as adduct resin with commercial tow-components polyurethane with proportion of 25%wt, 50%wt and...