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    Feasibility Study of Painting Line by Electro Deposition in Zagrosskhodro

    , M.Sc. Thesis Sharif University of Technology Fakouri, Hojjatollah (Author) ; Hooshmand, Mahmoud (Supervisor)
    Assurance about projects and industrial plans success always had been one of the most important concerns of investors. Car manufacturing industry is not excluded. In this project the painting line in zagrosskhodro company using electro deposition method is reviewed , analyzed, and investment feasibility study of such method is investigated . All aspect of investment including financial and economic aspect is reviewed by UNIDO methodology.
    The outcome is described here briefly.
    1- Production volume in this plan in complete capacity is equal to 40000 bodies in a year.
    2- The primary fixed investment capital is 132,187,912,140 Rls.
    3- Sum of fixed expenses of production is ... 

    Characterization of Nanohydroxyapatite-Carbon Nanotube on Stainless Steel 316L Produced by Sol-Gel Method

    , M.Sc. Thesis Sharif University of Technology Mohamadi, Pouya (Author) ; Nemati, Ali (Supervisor) ; Sadeghian, Zahra (Supervisor)
    In this investigation, hydroxyapatite-carbon nanotube nano composite coatings were applied on the 316L stainless steel implants. After polishing with 1200 sand paper, stainless steel implants were coated via dip coating method. The specimens were heat treated at 350˚C after being coated with HAP and HAP-CNTs composite. In vitro test was done in simulated body fluid (SBF) in 1 to 4 weeks periods. XRD evaluation of powder obtained from sol-gel process, showed the presence of HAP and CNTs in the powders. Comparison of XRD results of HAP and HAP-CNTs powders showed the better crystalinity of composite hydroxyapatite. After in vitro tests, specimens were studied with atomic force microscope (AFM)... 

    Fabrication of Ni -P -MoS2 Composite Coating by Electroless Deposition and Evaluation of Its Tribological Properties

    , M.Sc. Thesis Sharif University of Technology Majidian, Maryam (Author) ; Ghorbani, Mohammad (Supervisor) ; Afshar, Abdollah (Supervisor)
    Adding solid lubricant particles such as PTFE, Graphite and MoS2, has major influence on electroless composite nickel coatings in order to make low friction surfaces. Among these lubricants, MoS2 has attracted great attention due to its highest stability under wearing condition. In this work Ni-P-MoS2 composite coatings using MoS2 nano-particles have been made and in the next step, we evaluated tribological properties of these coatings. For exploring these coatings different experiments were utilized, like Scanning Electron Microscope study (SEM), chemical composition analysis exploiting AAS and XRF method, and thickness measurements. Two kinds of surfactants, CTAB and PVP, have been applied... 

    Lanthanum Chromite Coating on Stainless Steel by sol–Gel Dip Coating Technique

    , M.Sc. Thesis Sharif University of Technology Rashtchi, Hamed (Author) ; Faghihi Sani, Mohammad Ali (Supervisor)
    Because of the high operating temperature, interconnect surface tends to be oxidized and Cr2O3 oxide layer will be created on the surface. This phenomenon is undesirable due to decreasing electrical conductivity, so a preservative coating is needed to improve the interconnect properties. In this paper, a dense perovskite thin film was successfully synthesized on a ferritic stainless steel (type 430) substrate by a sol-gel dip coating method. This coating improved chemical stability, oxidation behavior of the substrate and decreased cathode poisoning. The lanthanum chromite was coated on the substrate by sol-gel dip coating process. First, during a hydrolyze process, a stable sol was made up... 

    Production of Cr-Al2O3 Nano-Composite Coatings by Electrodeposition

    , M.Sc. Thesis Sharif University of Technology Salehi Doolabi, Mohsen (Author) ; Sadrnezhad, Khatiboleslam (Supervisor)
    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... 

    Pulse Electrodeposition of Ni-ZrO2-MoS2 Composite Coatings and Its Tribological Properties

    , M.Sc. Thesis Sharif University of Technology Rajabi Khosh Andam, Mohsen (Author) ; Ghorbani, Mohammad (Supervisor)
    In this study solid lubricants MoS2 nanoparticles with average size 50 nm and hard ZrO2 nanoparticles with average size 51 nm were used in watts bath and Ni/ZrO2-MoS2 composite coatings were prepared by pulse plating technique. Effect of current density, frequency, duty cycle, surfactant type and concentration of particles in the electrolyte on the amount of particles in the coatings were investigated and optimum conditions were determined to create composite coatings. Scanning Electron Microscopy (SEM) and x-ray diffraction (XRD) analysis were performed to study the morphology, structure, chemical composition of coatings. Corrosion testing of coatings by potentiodynamic polarization in... 

    Production of Zn-Tio2 Nanocomposite Coating by Electrochemical Method and Investigation of its Properties

    , M.Sc. Thesis Sharif University of Technology Sajjadnezhad, Mohammad (Author) ; Ghorbani, Mohammad (Supervisor) ; Afshar, Abdollah (Supervisor)
    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.... 

    Characterization of Ceramic Coating Synthesized on Magnesium Alloy Substrate by Plasma Electrolytic Oxidation Process

    , M.Sc. Thesis Sharif University of Technology Rafizadeh, Ehsan (Author) ; Faghihi Sani, Mohammad Ali (Supervisor)
    Plasma electrolytic oxidation (PEO) is currently recognized as an effective coating method on active metals such as magnesium. In this method, through occurrence of strong electric discharges on the surface of the anode accompanied by electrochemical and thermo-chemical reactions at plasma environment, a relatively thick ceramic coating with complex compounds grows on the metal surface which significantly improves its properties. Regarding the influence of PEO electrical parameters on the morphology and other properties of the coating, the objective of the present study is to prepare a quality ceramic coating on AZ31 magnesium alloy substrate via setting the process parameters, such as... 

    Effects of Additives on Chromium Coating in Trivalent Chromium Bath

    , M.Sc. Thesis Sharif University of Technology Ebrahimi, Ghasem (Author) ; Dolati, Abolghasem (Supervisor)
    In this work, effects of different additives on trivalent Chromium bath and Chromium coating has been investigated. Malonic acid wich had been used as a complexing agent of the bath improved current efficiancy and coating quality obviously. Effects of Magnesum, zinc, Tin, Aluminium sulfates, Molybdic acid, TiO2 nano particles, Sodium hypophospite, formaldehead and mixtures of these compositions on hexavalent Chromium concentration of the bath were also studied. Concentration of Cr6+ ion decreased by 18 ppm due to adding these materials. Using Ti/ TiO2/ RuO2 Anode also could decrease Cr6+ concentration by 78 ppm. Remarkable results had been recorded in current efficiency and coating... 

    Investigation and Optimization of Ni-P-Zn Electroless Alloy Coatings

    , M.Sc. Thesis Sharif University of Technology Kordijazi, Amir (Author) ; karam, SaeedAllah (Supervisor) ; Dolati, Abolghasem (Supervisor)
    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... 

    Investigation on Synthesis and Properties of TiO2-CNT Nanocomposites Coating on Al Substrate

    , M.Sc. Thesis Sharif University of Technology Shadravan, Aysan (Author) ; Nemati, Ali (Supervisor) ; Sadeghian, Zahra (Supervisor)
    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... 

    Pulse Electrodeposition of Chromium Coating From Trivalent Bath and Studying it’s Properties

    , M.Sc. Thesis Sharif University of Technology Araban, Vahid (Author) ; Ghorbani, Mohammad (Supervisor) ; Dolati, Abolghasem (Supervisor)
    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... 

    The Structure and Corrosion Behavior of Synthesized Zn-SiO2 Nano-composite Coating by Sol-Gel Method

    , M.Sc. Thesis Sharif University of Technology Razavizadeh, Omid (Author) ; Ghorbani, Mohammad (Supervisor)
    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 2m has the lowest corrosion rate with the passive region in anodic branch. Corrosion... 

    Preparation and Stabilizing Graphene Sheets for Gas Sensing Application

    , M.Sc. Thesis Sharif University of Technology Mirmotallebi, Mona (Author) ; Iraji zad, Azam (Supervisor)
    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... 

    A Thermo-Mechanical Fatigue Life Prediction Model for Aluminum Alloy (A356.0) with Thermal Barrier Coating

    , Ph.D. Dissertation Sharif University of Technology Azadi, Mohammad (Author) ; Farrahi, Gholamhossein (Supervisor)
    Thermal barrier coating (TBC) systems have been widely used in gas turbines and diesel engines. Their advantages include reducing the fuel consumption, improving the performance and increasing the fatigue lifetime at high temperatures. In the present thesis, the fatigue behavior of an aluminum alloy (the A356.0 alloy), with and without a typical TBC system is studied. The application of this research can be introduced as coating the cylinder head in diesel engines. Initially, coating process parameters (including the feed rate and the nozzle distance) of the plasma spraying, with the objective of bending strength are optimized. The optimum value of the TBC thickness is obtained based on... 

    Effect of Fluorine Addition on Properties of Electrodeposited Fluorine-doped Hydroxyapatite Coating on AZ31 alloy

    , M.Sc. Thesis Sharif University of Technology Amirloo, Hossein (Author) ; Afshar, Abdollah (Supervisor)
    Magnesium and its alloys are potentialy biodegradable implant materials due to their attractive biological properties. But their poor corrosion resistance may result in sudden failure of the implants. Recently, many researchers have focused on applications of fluorine-doped hydroxyapatiteCa10(PO4)6(OH)2−xFx (FHA, x is the degree of fluoridation) as a bioactive coating to provide early stability and long-term performance. In comparison with pure HA coating,FHA coating could provide significant dissolution-resistant property, better apatite-like layer deposition, better protein adsorption, better cell attachment and improved alkaline phosphatase activity in cell culture. In this... 

    Effect of Intermediate Ni Layer on Glass-Stainless Steel Seal at Solid Oxide Fuel Cell

    , M.Sc. Thesis Sharif University of Technology Fakouri Hassanabadi, Masoud (Author) ; Kokabi, Amir Hossein (Supervisor) ; Nemati, Ali (Co-Advisor)
    In order to prevent deterioration of metallic interconnects in solid oxide fuel cells (SOFC), while interacting with glass-ceramic sealant, a nickel electroplated ferritic stainless steel (UNS 430) was used. After applying a layer of powdered glass (SiO2-B2O3-Al2O3-Na2O-BaO-K2O) with thickness around 300-450 μm on the ferritic stainless steel sheets with dimansion of 0.5 × 60 × 60 mm and 0.5 × 10 × 10 mm, samples were heated at temperatures between 770-850 °C and durations of 1 to 15 hours. To evaluate the effect of the Ni layer, two types of sample (only sanded and only electropolished) were also submitted to the same process, and their results were compared with the coated samples. XRF,... 

    Selection of a Nanostructured Pattern for Increasing Absorption Efficiency of a Solar cell Based Based on TiO2

    , M.Sc. Thesis Sharif University of Technology Daneshvare Asl, Shervin (Author) ; Sadrnezhad, Khatiboleslam (Supervisor) ; Mohammadi, Mohammad Reza (Co-Advisor)
    Dye–sensitized solar cell (DSSC) includes (a) A transparent conductive oxide coated glass substrate, (b) Semi conductive film, (c) Dye adsorbed on this film, (d) Redox couple electrolyte and (e) A counter electrode which can reduce redox couple.In this study, selection of a nanostructured pattern for increasing absorption efficiency of a DSSC based on TiO2 has been considered. For this purpose, using carbon nanotubes (CNTs) in fabrication of photoelectrode has been proposed. Therefore, at the first TiO2–CNT nanocomposites contained various percent of carbon nanotube was coated on fluorinated tin oxide (FTO) conductive glasses via sol–gel dip coating method. Then DSSCs were assembled by... 

    Simulation of Thermal Barrier Coatings under Thermo-Mechanical and Low Cycle Fatigue Loadings

    , M.Sc. Thesis Sharif University of Technology Rezvani Rad, Milad (Author) ; Farrahi, Gholamhossein (Supervisor)
    The main purpose in this thesis is the finite element simulation of thermal barrier coatings (TBC), subjected to residual stresses due to the coating process followed by thermo-mechanical fatigue loadings. This finite element modeling is performed in the ABAQUS software. In order to consider the actual condition of thermal barrier coating, models are defined based on a SEM image including real roughness and porosity of coating layers using image processing technique.
    Two-step residual stress taking into account both coating process of bond coat and top coat layer is performed. Pre- heating of substrate and bond coat in order to reach comperessive stresses in coating layers has been... 

    Nanostructural Coating of Al2O3 on NiTi Alloy Via Electrochemical Method for Improvement of Biomedical and Surface Properties

    , M.Sc. Thesis Sharif University of Technology Mahloujchi, Raziyeh (Author) ; Sadrnezhaad, Khatiboleslam (Supervisor)
    Nitinol alloy is important and increasingly used in medicine and industry due to its unique properties such as shape memory and superelasticity. Plasma Electrolytic Oxidation (PEO) is a relatively new method which in electrical discharge occurrence and formation of small plasma arcs on the anode surface and the electrochemical and thermochemical reactions in plasma environment prepare ceramic coating on the substrate. This method is taken into consideration because of its simplicity and effectiveness in the preparation of oxide ceramic coatings with porous structure on the surface of certain metals and alloys to improve their corrosion and wear properties. In this study, to improve the...