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titanium
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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...
Synthesis and Study of Application of MXene (Ti3C2) Layered Materials in Supercapacitors
, Ph.D. Dissertation Sharif University of Technology ; Iraji Zad, Azam (Supervisor) ; Esfandiar, Ali (Supervisor)
Abstract
In recent years, MXenes, a class of 2D materials, have drawn significant interest because of their special properties and layered structures. Among the MXenes family, Ti3C2 is a promising candidate in energy storage field due to its unique electrical conductivity, hydrophilicity, surface redox reactions, excellent packing density and high volumetric capacitance. In this thesis, synthesis and supercapacitor application of Ti3C2 have been investigated. HCl and LiF solution and mild exfoliation method has been used for etching Al layers from Ti3AlC2 and MXene synthesis. To analyze the structure of this material, scanning electron microscopy, atomic force microscopy, X-ray diffraction...
Notch-texture strengthening mechanism in commercially pure titanium thin sheets
, Article Materials and Design ; Vol. 55, issue , March , 2014 , p. 683-689 ; Abbasi, R ; Ekrami, A ; Ziaei-Moayyed, A. A ; Sharif University of Technology
Abstract
Simultaneous effects of notch and texture on strengthening mechanisms of rolled thin sheets of commercially pure titanium were investigated. The presence of notch led to the restriction of deformation systems and different fracture behaviors compared to un-notched specimens. The loss of material's ability to accommodate plastic deformation at the notch tip with increase in rolling reductions changed the notch strengthening phenomenon to the notch weakening one. At medium levels of deformation, due to the simultaneous development of a triaxial stress state and strong basal texture at the notch tip, a new strengthening mechanism which is called "notch-texture strengthening mechanism" led to a...
Impact of phase transformation on mechanical properties anisotropy of commercially pure titanium
, Article Materials and Design ; Volume 37 , 2012 , Pages 223-227 ; 02641275 (ISSN) ; Ekrami, A ; Ziaei Moayyed, A. A ; Sharif University of Technology
Abstract
Effects of microstructure and texture, before and after phase transformation, on the anisotropy of the mechanical properties and fracture behaviors of commercially pure titanium were studied. Before phase transformation, due to the split distribution of basal texture the activation of different deformation systems led to mechanical properties anisotropy. Although the fracture mechanism in both specimens was voids nucleation, growth and coalescence, the shape, size and distribution of dimples were affected by active deformation systems. However, after phase transformation, basal plains in most grains were aligned with the transverse direction. This texture component led to the activation and...
An enhancement in the photocatalytic activity of TiO 2 by the use of Pd: The question of layer sequence in the resulting hierarchical structure
, Article Journal of Coatings Technology Research ; Volume 8, Issue 1 , January , 2011 , Pages 75-81 ; 15470091 (ISSN) ; Ghorbani, M ; Mohsenzadeh, M ; Sharif University of Technology
2011
Abstract
TiO 2 and Pd-modified TiO 2 photocatalysts were prepared by sol-gel method. X-ray diffraction (XRD) data showed that the presence of Pd in TiO 2 catalyst decreases the crystalline size of TiO 2 and stabilizes anatase phase. The study of the photocatalytic activity of the films via Linear Sweep Voltametry (LSV) plots and antibacterial test against Escherichia coli ATCC 25922-a gram negative bacterium-showed that Pd increases the photocatalytic activity of the coatings. Besides, the sequence of layer deposition (TiO 2 and Pd-modified TiO 2) influences the photocatalytic properties. In other words, more photocatalytic activity is obtained when Pd-modified layer is deposited first
Fabrication of self-organised highly ordered titanium oxide nanotube arrays by anodic oxidation and characterisation
, Article International Journal of Nanomanufacturing ; Volume 5, Issue 3-4 , 2010 , Pages 297-309 ; 17469392 (ISSN) ; Ahadian, M. M ; Iraji Zad, A ; Taghavinia, N ; Dolati, A. G ; Sharif University of Technology
2010
Abstract
Self-organised and vertically oriented titanium oxide nanotube array (TNTA) has been synthesised by potentiostat anodisation of Ti foil in fluoride-based electrolyte. By varying the anodisation voltage from 8 V to 24 V it was possible to gradually change the topologies of nanotubes. The size of TNTAs was measured using SEM images and also determined based on a non-destructive optical method. In addition, photoelectrochemical properties of nanotubular TiO2/Ti electrodes were examined by anodic photocurrent response, potentiodynamic polarisation measurements and electrochemical impedance spectroscopy. A general equivalent circuit model was proposed for photoelectrochemical system consists of...
Photo-detector diode based on thermally oxidized TiO2 nanostructures/p-Si heterojunction
, Article Journal of Applied Physics ; Volume 119, Issue 1 , 2016 ; 00218979 (ISSN) ; Shasti, M ; Ramezani Sani, S ; Mortezaali, A ; Sharif University of Technology
American Institute of Physics Inc
Abstract
Titanium oxide (TiO2)-based photodetectors were fabricated using a thermal oxidation technique. The effect of two different annealing temperatures on morphology, structure, and I-V characteristics has been investigated. TiO2/Si heterostructure exhibited diode-like rectifying I-V behavior both in dark and under illumination. Dependence in photoresponse on annealing temperature was observed that was related to effective surface area of quasi-one-dimensional TiO2 nanostructures. Fabricated TiO2/Si diodes in 850 °C as the lower annealing temperature showed higher responsivity and sensitivity compared with grown ones in 950 °C (R850 °C/R950 °C ∼ 5 and S850 °C/S950 °C ∼ 1.6). Rather good...
Biomimetic synthesis of calcium phosphate materials on alkaline-treated titanium
, Article 29th Annual International Conference of IEEE-EMBS, Engineering in Medicine and Biology Society, EMBC'07, Lyon, 23 August 2007 through 26 August 2007 ; 2007 , Pages 5853-5856 ; 05891019 (ISSN) ; 1424407885 (ISBN); 9781424407880 (ISBN) ; Behnamghader, A ; Afshar, A ; Ardeshir, M ; Forati, T ; Sharif University of Technology
2007
Abstract
The hydroxyapatite coating on metal implants is a suitable method to create a bioactive surface and to increase the bone-implant bonding strength. In this research, at first the titanium surface was treated with NaOH solutions ; 5N and 10N at 60°C for 24 h and 5N at 60°C for 24 h followed by heating at 600°C for 1 h. The samples were immersed in the simulated body fluid (SBF) for 28 days to generate a calcium phosphate coating on titanium substrates. The modified substrates and coatings were characterized using SEM and XRD. According to the results obtained in this work the concentration increase of the NaOH solution has influenced the grain boundaries, whereas the heat treatment at 600°C...
Microstructure and cutting performance investigation of Ti(C, N)-based cermets containing various types of secondary carbides
, Article International Journal of Machine Tools and Manufacture ; Volume 47, Issue 5 SPEC. ISS , 2007 , Pages 768-772 ; 08906955 (ISSN) ; Rahmani, M ; Faghihi Sani, M ; Nemati, Z ; Akbari, J ; Sharif University of Technology
Elsevier Ltd
2007
Abstract
In this paper, the effects of type and amount of various secondary carbides on the microstructure and cutting performance of Ti(C0.7N0.3)-12Co system have been investigated. Nine alloys with different amounts of WC, Mo2C and Ta0.7Nb0.3C additives were studied, using scanning electron microscopy (SEM), Vickers hardness (HV), transverse rupture strength (TRS) and continuous turning tests. Alloys including Mo2C and WC presented finer carbonitride grain structure, as well as higher wear resistance resulting from their higher hardness and highly solution hardened binder phase. © 2006 Elsevier Ltd. All rights reserved
Wear-Resistant Nickel-Titanium Nitride Composite Coating by Electrochemical Method
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
Metal matrix nanocomposites contains ceramic ultrafine particles in a metal matrix, are used to improve the mechanical properties such as hardness and wear of coatings. For developing metal matrix nanocomposites, there are many methods. Electrochemical deposition process is one of these methods that have some advantages like uniform depositions on substrates with complex shapes, low cost, good repeatability and reducing waste. In this project, for increasing the hardness and wear resistance of nickel, composite coatings of nickel - titanium nitride was created by using electrochemical deposition of Watts bath contained titanium nitride particles. In order to increase the amount of...
Production of Al-TiO2 composite layer by friction stirs processing
, M.Sc. Thesis Sharif University of Technology ; Kokabi, Amir Hossein (Supervisor) ; Maddah Hosseini (Co-Advisor)
Abstract
In this study, Al-TiO2 composites layer were produced on Al 1100 substrate using friction stir processing technique. The variation of process parameters such as tool rotational and substrate advancing speed as well as number of FSP passes were adjusted to achieve quite uniform dispersion of Nano-particles in the Al matrix of the fabricated surface layer. Microstructural observations were carried out using optical and scanning electron microscopes. By increasing the FSP passes, uniform distribution of TiO2 particles in the matrix improved. Surface composition layer exhibited a micro-hardness value of 49 HV which was around twice of the as-received substrate. In addition wear resistance of...
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...
Synthesis and Characterization of Electrophoretic Deposited One- Imensional Nano Structured Titania
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza (Supervisor) ; Khomamizadeh, Farzad (Supervisor)
Abstract
Recent studies have indicated that one-dimensional titanium dioxide (TiO2) shows excellent properties in comparison to other forms of TiO2 materials in photocatalysis, sensing, self-cleaning coating and photovoltaic applications. In this project TiO2 nanorods were grown in polycarbonate template, with pore diameter of 200 nm, by solelectrophoretic deposition method. Firstly, properties of TiO2 sol were investigated. The average particle size of TiO2 (measured by zeta sizer instrument) was 17 nm and the zeta potential was around 45 mV, which confirmed good stability of the sol against aging. Moreover, FTIR analysis showed that a full conversion of precursor (titanium isopropoxide) was...
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...
Synthesis of ZnO and ZnO-TiO2 Nanocoatings by Sol-Gel Methode and Study in Their Antibacterial and Photocatalyst Properties
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
The goal of this study is synthesis of nanocoating on basis of ZnO by Sol-Gel method and evaluation of their antibacterial and photocatalyst properties changes by different values of TiO2. For this purpose in both method of synthesis contents of TiO2 hase been changed from 0-25 molar percent. Dip coat method has been used for coating from sol with 1.4 mm/s withdrawal speed and 2 minute immersion time. After each step of coating samples has been dried at 150oC for 10 minute and for increasing thickness this process has been repeated 4 times. In first method zinc acetate dihydrate in 0.1 M final concentration and titanium tetraisopropoxide are sol precursors at in situ way of synthesis. In...
Microemulsion Synthesize of Fe3O4/TiO2 Core-Shell Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Madaah Hoseini, Hamid Reza (Supervisor)
Abstract
In this study magnetite nanoparticles were synthesized by microemulsion and were coated with TiO2 by a precipitation technique. The synthesize process were done under fixed molar ratio of various constituents of microemulsion and molar ratio of water to oil. Results of X-ray diffraction spectroscopy (XRD) showed that the uncoated nanoparticles were consisted of magnetite as the major phase and no other detectable phases such as pure iron or hematite were found. Field emission scanning electron microscopy (FE-SEM) results showed that the synthesized nanoparticles small size and narrow particle size distribution. For TiO2 coating process the effect of TBOT concentration, water concentration,...
Ionization and Dissociation of the Chlorine Molecule by the Femtosecond Ti: Sapphire Laser Radiation
, M.Sc. Thesis Sharif University of Technology ; Sadighi-Bonabi, Rasoul (Supervisor)
Abstract
Ionization probability of Cl2 molecule is studied by irradiation of 800 nm Ti: Sapphire laser pulses at intensities of 1014 Wcm-2 to 1016 Wcm-2 with the Gaussian package. Molecular orbital symmetry and orientation of the molecule dipole moment with laser field polarization axis are very effective in ionization probability. The results show that the most ionization probability for the intensity of 1014 wcm-2 is at 900 and also 50 at intensity of 1016 wcm-2. Due to the lack of intrinsic dipole moment, variation of dipole moment with the intensity, bond length and time evolution of dipole moment are investigated. It is found that there is a linear dependance of these parameters with ionization...
Study on Nucleation and Growth of Titanium Dioxide Nano Particles via Gel-Sol Method
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Nanotechnology is an efficient method suitable for fabrication and production of minimal single dimensional nanometric structures. Such materials and systems can be logically designed that lead to new and optimized biological, chemical and physical properties and characteristics due to their size. Nucleation and growth –appearance of a new phase out of an old phase – is a ubiquitous phenomenon in nature. Fundamental understanding of nanoparticles nucleation and growth mechanism allows more control on form, size and composition and allows tuning of the above said properties easily with use of different reactive conditions as a result of this ability . Nanoparticles of titania are one of...
Investigation on Effective Parameters in Ceramic Coating on Titanium Substrate by PEO Method in Galvano Static Condition
, M.Sc. Thesis Sharif University of Technology ; Faghihi Sani, Mohammad Ali (Supervisor)
Abstract
During this research, ceramic coatings on titanium substrate were prepared by plasma electrolytic oxidation process at a constant current density. Effect of different parameters such as frequency, current density, additives and time on the characteristics of the coated samples was studied. Composition, structure and elemental distribution of the coatings were studied by XRD, SEM and wave-length dispersive spectroscopy (WDS), respectively. Various tests were carried out to calculate the amount of coatings porosity. Pin-On-Disk method was used to evaluate erosion resistance of coatings. Corrosion and erosion-corrosion behaviors of the coatings were studied in 3.5wt% sodium chloride aqueous...
Synthesis of Pure Titanium Nanoparticles by Electromagnetic Levitation Melting Gas Condensation
, M.Sc. Thesis Sharif University of Technology ; Halali, Mohammad (Supervisor)
Abstract
High purity titanium nanoparticles were synthesized by utilizing Electromagnetic Levitation Melting Gas Condensation (ELM-GC) method. High purity titanium samples were melted by electromagnetic levitation to a temperature of 1700 ± 20 °C in a silica tube. High purity argon and helium were employed as carrier gases and cooling agent. Particlesize, morphology, and Purity of the produced nanoparticles were studied by Field-Emission Scanning Electron Microscopy (FE-SEM), X-ray Diffraction (XRD), Dynamic Light Scattering (DLS), X-ray fluorescence (XRF), and ICP-AES analysis. The FE-SEM, DLS and XRF studies confirmed narrow size distribution of almost spherical shape pure titanium nanoparticles...