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Investigation on Effective Parameters on Mold Filling of Cast Iron Melt in EPC Process
, M.Sc. Thesis Sharif University of Technology ; Varahram, Naser (Supervisor)
Abstract
Casting process with foam is a relatively new process which because of having multiple benefits (like elimination of muscle and segregation line, high dimensional precision and using sand without using glue) in recent years has been considered. Considering that during pouring, melt replaces with sand surrounded foam, successfulness of this method depends on complete elimination of foam model during Pouring for preventing formation of some defects like carbon defects in cast irons, or cold work and porosity in aluminum alloys. Parameters like Pouring temperature, alloy type, foam type, density of foam model, type of gating system, and some other parameters are affecting the way of filling of...
Probing the Performance of Safflower Plant as a Green Inhibitor with Molybdenum Disulfide on Corrosion Protection Properties of the Epoxy Coating
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadat Abadi, Ahmad (Supervisor) ; Mahdavian Ahadi, Mohammad (Supervisor)
Abstract
Today, the process of corrosion and compensation of minor injuries, without the need for tracing or any other physical interference, has become one of the subjects of interest to researchers. Inhibitors have been considered as one of the anti-corrosion agents. In this research, safflower extract as a green inhibitor in sodium chloride corrosive environment was used to evaluate the rate of corrosion of mild steel. Also the MoS2 nanoparticles were used as carrier of this green inhibitore in the epoxy coating to allow the activation of the coating in a scratched state in sodium chloride solution of 3.5%. In the first step, the extract of the safflower was prepared to reach the best part of this...
Super Hydrophobic Ni Coating on Steel by Electrodeposition Method
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
In this study, the properties of super-hydrophobic Ni coating on carbon steel including wetting behavior and corrosion resistance of Nickel coatings deposited on the steel substrate were investigated. For this purpose, Nickel coatings deposited by electrodeposition method in deferent current density (10,20,30,50, 70 mA /cm2) in bath containing 1.5 mol of ethylene de-ammonium de-chloride, 0.5 mol H3BO3, 1 mol Nicl2.6H2o and then immersed in a bath containing 0.01 mol per liter myristic acid and ethanol for 24 hours and then placed in the room temperature for 14 days. Deferent tests were used for characterization, wettability properties, corrosion behavior and morphology of Ni coatings. The...
Antistatic Polyurethane Coating Containing Zirconia Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
In this study, antistatic waterborne polyurethane coating containing zirconia nanoparticles is made and applied on 304 stainless steel substrates at weight percentage of 0.66, 1.3, 3, 4.5 and 6% zirconia nanoparticles. For synthesis of hydrophilic isocyanate prepolymer, isocyanate prepolymer is modified by hydrophilic polyethylene glycol with molecular weight 600, 1000 and 4000. For ensuring of modification condition and stability of hydrophilic isocyanate prepolymer in aqua solution, FTIR and stability tests are employed, respectively. In order to create antistatic properties of these coatings, semi - conductive zirconia nanoparticles are used. To improve the distribution of zirconia...
Estimation of Chitgar Lake Evaporation and the Impact of Chemical Coverings on its Reduction
, M.Sc. Thesis Sharif University of Technology ; Tajrishy, Masoud (Supervisor) ; Irajizad, Azam (Supervisor)
Abstract
Reducing water evaporation is one of the ways to overcome the low precipitation and drought conditions in water reservoirs. For this purpose, extensive studies have been investigated on physical and chemical coatings on lakes and reservoirs. Physical methods often involve the use of floating covers on the water surface to block evaporation by shading, most of which are only suitable for reservoirs with surface areas smaller than 5 hectares. In chemical methods, the evaporation can be decreased by nanomaterial coating, usually, containing long-chain molecules, which by spraying them on the surface, molecular monolayers are formed. In this study, the effect of nanometer coatings on the surface...
Experimental Investigation of Performance of Tack Coats
, M.Sc. Thesis Sharif University of Technology ; Tabatabaee, Nader (Supervisor)
Abstract
In this study performance of tack coat (thin layer bonding asphalt concrete layers) was evaluated. The shear strength of tack coat layer was considered as its measure of performance. Direct shear tests were conducted on two layered HMA specimens. The test variables included the type of tack coat material, application rate (amount of residual bitumen per unit area), substrate condition, normal stress and shear loading rate. Four types of liquid asphalt (CSS, CRS, modified CRS and MC-250) were applied as tack coat. Three substrates conditions were used in the tests. These were 3-days old, 17-days old and long term aged substrates were used. It was found that optimum application rate depends...
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...
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...
Preparation and Stabilizing Graphene Sheets for Gas Sensing Application
, M.Sc. Thesis Sharif University of Technology ; Iraji zad, Azam (Supervisor)
Abstract
Graphene is one of the most attractive subjects for scientists in the last decade. Its unique properties has been probed by many research groups and innumerable projects have been developed to investigate applications of graphene in electronics, mechanics, biophysics etc. Due to high surface to volume ratio and magnificent electron mobility in graphene, it is a suitable candidate for gas sensing. This has been proved by several theoretical and experimental researches for various gases such as CO, NH3 and NO2 etc. In present thesis, graphene has been prepared chemically and transferred to silicone substrates that are previously coated with a 300 nanometer silicone dioxide layer, by dip...
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...
The Effect of Pomegranate Peel Extract as a Green Anti-corrosion Agent and Aluminium Oxide Nanostructured Containing Sulfur on the Anticorrosion
Performance of Epoxy Coating
,
M.Sc. Thesis
Sharif University of Technology
;
Ramazani Saadatabadi, Ahmad
(Supervisor)
Abstract
The present work focuses on the sustainable development of an intelligent self-healing anticorrosion coating using nanocontainers based on the aluminium oxide nanostructure-pomegranate peel extract-Ce3+ (Ce-PPE@Cat). The Ce-PPE@Cat nanopigment was introduced into the epoxy film (Ep) to achieve a smart barrier/ self-healing anti-corrosive property. To this end, a couple of characterization tests, including FT-IR, TGA, and, BET have been carried out to investigate the Ce-PPE@Cat nanopigment structure/composition. The effectiveness of the anti-corrosion performance of the established coatings was confirmed by EIS, FE-SEM, and accelerated salt spray test. Furthermore, EIS studies revealed that...
Functional Design of a Coating System for the Telescope Mirrors, A Recognition to Telescope of Iranian National Observatory
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Alireza (Supervisor) ; Khosroshahi, Habib (Co-Advisor)
Abstract
Functional design of coating system for the primary mirror of the Iranian National Observatory (INO) is done. This telescope has a 3.4 m primary mirror in diameter, made of Zerodur from Schott. Although similar coating systems are in use since years ago, this is the first attempt to design a system for such a large surface case in Iran. Systematic approach led us first to clarify and identifying the design requirements. Lower limit of 80% for reflectance on all wavelength range from 325-1000 nm, thickness of 100 nm with un-uniformity of 5 nm, adhesion enough to pass the selotape test and surface roughness of less than 8 nm. Study of the available methods for coating and selection of the best...
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...
Fabrication and Microstructual Study of Ti/TiC Composite Coating on CP-Ti by Using Various Cored Wires and TIG
, M.Sc. Thesis Sharif University of Technology ; Kokabi, Amir Hossein (Supervisor) ; Asgari, Sirous (Supervisor)
Abstract
Tungsten Inert Gas (TIG) process and different cored wires that were filled separately with nano TiC particles, micro TiC particles and graphite powders were employed to produce surface composite coating on CP-Ti substrate to improve wear resistance. At first using titanium strips, wire drawing process and different powders various cored wires were produced and then using TIG, these cored wires were coated on CP-Ti. This process was done for different current intensities and velocities. Composite coating tracks were found to be affected by the TIG heat input and the kinds of the cored wires. The microstructures of the surface composite coating showed phases of α'-Ti and primary and dendritic...
Effective Factors on the Shrinkage Porosity Defect of Ductile Iron in Centrifugal Casting
, M.Sc. Thesis Sharif University of Technology ; Varahram, Naser (Supervisor) ; Davami, Parviz (Supervisor)
Abstract
The present work has been planned to elaborately investigate the key parameters which affect the formation of shrinkage porosities during centrifugal casting of ductile cast iron pipes. The porosity defects can be mostly found in the Hot Mould centrifugal casting products and adversely affect the final mechanical properties of ductile iron pipes namely Ultimate Tensile Strength and Elongation.
In the first point of view, the created defects were detected through microstructural observations and the corresponding responsible mechanisms were also discussed. The results showed that the inner porosity is produced because solidification occurs from both the inner and outer surfaces...
In the first point of view, the created defects were detected through microstructural observations and the corresponding responsible mechanisms were also discussed. The results showed that the inner porosity is produced because solidification occurs from both the inner and outer surfaces...
Improvement of Corrosion Resistance of Concrete Sewer Pipes Against Microbial Corrosion
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
Microbiologically Influenced Corrosion (MIC) of concrete sewer ptpes and wastewater collection systems has been reported in many places of the world. Recently, numerous copper compounds have been used for bacterial growth control in sewer pipes. In this thesis, bath parameterswere optimized in order to maximize copper osmosis to the porous concrete matrix.Concrete pipes were electrochemically coated inCopper Lactate bath in a constant current mode (1=0.6 A), while temperature was set to 25, 50, 75 and 95
°Cand pH to 9,10 and 11. Specimens were then characterized by scanning electron
microscopy, optical microscopy, XRD andAAS. Copper Osmosis was highest in pH=9 and...
°Cand pH to 9,10 and 11. Specimens were then characterized by scanning electron
microscopy, optical microscopy, XRD andAAS. Copper Osmosis was highest in pH=9 and...
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...
Preparation and Characterization of Asymmetric and Thin Film Composite Nanofiltration Membranes for Water Softening
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor) ; Roosta Azad, Reza (Supervisor)
Abstract
In this study three type of nanofiltration membranes were prepared from PVC for water softening; (i) asymmetric PVC nanofiltration membrane, and two different thin film composite (TFC) membranes: (ii) polyamide (PA)/PVC composite membrane (iii) poly vinyl alcohol (PVA)/PVC composite membrane. Asymmetric nanofiltration membranes were prepared by phase inversion. The effect of PVC concentration, solvent (THF) and additive (PVP) on morphology and performance were studied by scanning electron microscopy (SEM) and measuring pure water flux and salt rejection. Increasing PVC concentration decreased pure water flux and increased salt rejection. Adding tetrahydrofuran(THF) decreased the pure water...
Improving Mechanical and Biological Behavior of Mg-2ag Alloy: Effects of Y Addition, Heat Treatment and Coating
, M.Sc. Thesis Sharif University of Technology ; Alizadeh, Reza (Supervisor)
Abstract
Biodegradable Mg-Ag alloys are promising implants for bone tissue regeneration due to their unique ability to reduce inflammation and infection after implantation with the presence of silver. However, their biological performance, including biodegradability, needs further improvement. In this regard, the effects of adding yttrium element, solution heat treatment and coating on the microstructure, biodegradability behavior, mechanical properties and biological characteristics of a cast Mg-2Ag alloy were studied. Addition of 1 wt% of yttrium caused grain refinement in the microstructure and solid solution heat treatment led to a significant decrease in the volume fraction of secondary phases....
Investigation of Si3n4 Nano Particle Addition on the Hardening Behavior of Anodized Coated 1050 Aluminum Alloy
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
In the present study, it has been tried out to increase the hardness and wear resistance of anodized aluminum coating byadding Si3N4 nanoparticles to the anodizing bath and making a composite coating. In order to investigate the influence of other effective parameters on the properties of anodized coating before the compositing process, hardness and thickness were optimized in the Sulphoric/oxalic bath using design of experimental method (central composite design). The properties of these coatings are dependent on various parameters among which time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were considered in the present study. Analysis of...