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nanostructured-coating
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Enhanced Photocatalytic Activity of Nano-scaled TiO2 Co-doped with N and Ag by Sol-gel Method
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
Transparent coatings with self-cleaning property in visible light spectrum, UV radiation resistance and antimicrobial are highly desirable. Titanium dioxide (TiO2) is used in this research has been widely studied as an efficient photocatalyst by researchers. In this research enhanced visible-light photocatalytic activity is gained with N and Ag co-doped titania. All samples were annealed at 450℃. Finally AgI was loaded TiO2 coating and the results were investigated. Peaks of XRD pattern wereattributed to different diffraction planes of anatase TiO2. Morphology of coatings were analyzed with using FE-SEM. Nano granis size of TiO2 and AgI loaded TiO2 were observed in FE-SEMimages. Nitrogen...
Nanostructural Coating of Al2O3 on NiTi Alloy Via Electrochemical Method for Improvement of Biomedical and Surface Properties
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhaad, Khatiboleslam (Supervisor)
Abstract
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...
Loading of Drug and Nanostructured Coating on Dental Implant
, M.Sc. Thesis Sharif University of Technology ; Sadrnezhaad, Khatiboleslam (Supervisor)
Abstract
The aim of this project is to load analgesic drug; Paracetamol on dental implant. The implant is titanium alloy (Ti-6Al-4V). There are two kinds of samples of anodized and HA coated onto anodized. They are in the shape of the sheets in this study. The electrodeposition and anodization carried out in order to treat the two samples. Nanotubes were formed during anodic oxidation of the samples in the 1M Ammonium sulfate (NH₄)₂SO4 and 5wt% Ammonium fluoride NH4F electrolyte. They are expected to play role of carrier for the model drug; paracetamol. The results showed that HA anodized Ti-6-4 has the ability to hold higher amounts of drug and also can keep the drug for a longer time than the...
Investigating Effect of Nano Ceramic Coating of Combustion Chamber on the Performance of Internal Combustion Engines
,
M.Sc. Thesis
Sharif University of Technology
;
Naghdabadi, Reza
(Supervisor)
Abstract
Thermal barrier coatings (TBCs) are used for increasing the efficiency and reducing pollutants of internal combustion engines (ICEs). In this paper, an optimization framework is developed in order to obtain the optimal dimensions for conventional coat, and the optimal dimensions and material property for functionally graded (FG) coat of a partially coated piston. A thermo mechanical analysis is investigated for Nano coat by finite element method. The conventional and Nano coats are made of MgZrO_3 as the insulating ceramic overlay and NiCrAl as the metallic bond-coat. The properties of the FG coat is assumed to vary according to power law through the thickness. For all tree conventional, FG...
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...
Titania nanostructured coating for corrosion mitigation of stainless steel
, Article Protection of Metals and Physical Chemistry of Surfaces ; Vol. 50, issue. 3 , 2014 , p. 371-377 ; Sani, M. A. F ; Sadeghian, Z ; Ghasemi, H ; Sharif University of Technology
Abstract
Anatase nanostructured coating has been prepared on 316 L stainless steel by sol-gel dip coating. The topography of the coatings surface has been analyzed using atomic force microscopy. The anticorrosion performance of the coatings has been evaluated using polarization curves. Effects of calcination temperature, withdrawal speed and times of coating on corrosion protection have been studied. The results showed calcination temperature of 400°C and withdrawal speed of 10 cm/min are desirable conditions to achieve high corrosion protection of 316 L stainless steel in chloride containing environments. Coatings with 3 times exhibit better resistance against corrosion in 0.5 molar NaCl solutions....
Preparation of uniform TiO2 nanostructure film on 316L stainless steel by sol-gel dip coating
, Article Applied Surface Science ; Volume 255, Issue 20 , 2009 , Pages 8328-8333 ; 01694332 (ISSN) ; Sani, M. A. F ; Ghasemi, H ; Sadeghian, Z ; Mirhoseini, S. M. M ; Sharif University of Technology
2009
Abstract
Sol was prepared by the mixing of tetra-η-butyle titanat, ethyl aceto acetate, and ethanol in an optimized condition. Polished 316L specimens were coated with the sol by dip-coating method. The influences of drying condition, withdrawal speed, calcination temperature, addition of dispersant, and pH of sol on TiO2 nanostructure coating were investigated. Choosing of alcohol as drying atmosphere hindered the crack formation. The relation between coating thickness and withdrawal speed was evaluated. The optimum temperature to create a uniform distribution of nanoparticles of anatase was derived as 400 °C. Average roughness of coating was found about 10.61 nm by AFM analysis. Dispersant addition...
Fabrication of Nanostructure Cuprous Oxide Films for Photovoltaic Systems
, Ph.D. Dissertation Sharif University of Technology ; Iraji Zad, Azam (Supervisor) ; Mohammadpour, Raheleh (Supervisor)
Abstract
Metal oxide semiconductors are promising materials for photovoltaic systems, because they are chemically stable, almost non-toxic and abundant. These materials are cheap and have low cost fabrication process. Cu2O is the most popular metal oxide semiconductor to absorb light in Photovoltaic (PV) applications, and photocathode in the photoelectrochemical systems.In this project, thermal oxide and electrodeposition methods, both interesting and cheap, were applied for preparing Cu2O films. As inexpensive materials results in low-minority carrier diffusion length, we report on surface engineering of bulk Cu2O photocathode thorough employing nanorods of copper oxide with the average lengths of...
Al2O3-ZrO2 nanostructured coatings using DC plasma electrolytic oxidation to improve tribological properties of Al substrates
, Article Applied Surface Science ; Volume 356 , November , 2015 , Pages 927-934 ; 01694332 (ISSN) ; Meletis, E. I ; Golestani Fard, F ; Yerokhin, A ; Rastegari, S ; Faghihi Sani, M. A ; Sharif University of Technology
Elsevier
2015
Abstract
Alumina-zirconia nanostructured coatings were formed on 7075 Al alloy through Plasma Electrolytic Oxidation (PEO) operated in aDC potentiostatic mode. The composite coatings were produced in the range of 425-500 V in an alkaline electrolyte containing 4 g/LK2ZrF6. Tribological properties of coatings were investigated using dry sliding wear test against WC balls with a pin-on-disc tribometer. Wear rates were evaluated using optical profilometer. It was shown that the nanostructured alumina-zirconia composite coatings can be formed at voltages 450 V. The coating thickness and roughness were in the range of 15.2-24.2 μm and 0.68-2.35 μm, respectively. The distribution of Al, Zr and O in the...
Optimization of nano HA-SiC coating on AISI 316L medical grade stainless steel via electrophoretic deposition
, Article Materials Letters ; Volume 285 , 2021 ; 0167577X (ISSN) ; Ahangari, M ; Johar, M. H ; Allahkaram, S. R ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Biocompatible nanostructured coating plays an important role in enhancement of osseointegration ability of metallic implants. This study sets out to obtain optimized SiC concentration in Hydroxyapatite (HA) coating on AISI 316L stainless steel alloy through electrophoretic deposition method. Effect of SiC concentrations (1, 2, and 3%.wt) on the morphology, corrosion behaviour, and mechanical properties of the HA coating is investigated. Results show that SiC could obstruct the formation and growth of micro cracks in the HA coating where HA-3%SiC is considered as a crack free coating. Electrochemical tests reveal that SiC has improved the corrosion resistance of HA coating, and HA-3%SiC...