Sharif Digital Repository

Titanium dioxide, due to its specific semiconductive properties, has been a highly investigated material for a variety of applications including gas sensors, hydrogen generation by water photoelectrolysis, photocatalysis, dye-sensitized solar cells and purification of water and air. Several recent studies have indicated that titania nanotubes have improved properties compared to any other form of titania for mentioned application. Titania nanotubes have been produced by a variety of methods including deposition into a template and hydrothermal processes. Anodic oxidation of titanium foil in a fluoride-based solution is one of the best methods to produce of titania nanotube arrays. Highly... 

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... 

The present work describes sensing application of modified TiO2 nanotubes towards detection of dopamine. The TiO2 nanotubes electrode was prepared using anodizing method at different conditions, among which NaF/ NaHSO4 solution and voltage of 15 V was chosen as the optimum condition. In order to improve the performance, surface modification with metal nanoparticles (Pd, Pt and Au) and carbon is required using “pulse electrodeposition” and “decomposition of polyethylene glycol at 600 °C” respectively. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. In this regard two type of electrodes were proposed: Pd-Pt-Au-TiO2 and C-Ni(Pt)-TiO2.... 

In this research, first thin films with nanostructures of titanium nanotube arrays (TNAs) synthesized by anodization under different applied voltage (20- 60 V) and different reaction times (120 and 200 min). The electrolyte solution for synthesizing the samples contained 90% ethylene glycol (EG), 10% DI water, 0.1 M NHR4RF and a little HR3RPOR4R to reach the pH to 5.6. The synthesized samples crystallized under annealing treatment at 500 °C (with heating rate of 9.5 °CminP -1 P). The scanning electron microscopy (SEM) analysis was indicate that the length and the inner diameter of the nanotubes have increased from 1.6 μm and 67 nm (for 30 V anodization and for 2h) to 4.2 μm and 125 nm (for... 

The use of dental implants has grown considerably in recent years in Iran but this piece is the industrial imported parts that are not yet produced in Iran. So the main purpose of this research was to fabricate a dental implant from Ti-6Al-4V alloy by CNC machining techniques. On the other hand, the poor bonding strength of bioactive coatings and low cell growth on the surface of uncoated implants are the common problems in the use of dental implants. So another aim of this study was to investigate the effect of Nanoscale surface topography and nanostructured coatings on the surface modification of titanium implant in order to improve Osseointegration and the bonding strength of bioactive... 

In recent decade, photocatalystic properties of titania nanotube and its mechanisms has been considered greatly in many researches. One of the major ways to increase photocatalystic properties and extending the usage of TNTs is doping them with various elements and modifying their band structure. In present research doped TNTs were prepared by doping of Molybdenum, Nitrogen, and Carbon elements by anodizing method in about of 35 degrees of centigrade and constant voltage of 20V on the surface of titanium sheet. Structural and photocatalystic properties of as-prepared TNTs were studied using field emission scanning electron microscope (FESEM), x-ray diffraction (XRD), energy dispersive... 

In this study anodized none composite and composite film containing ZrO2 nanoparticles were prepared on 1050 Al Alloy using hard anodizing method in sulfuric and oxalic acid mixed solution by pulse Currents. The microstructure and properties of the film were studied by field emission scanning electron microscopy with EDS analyzer and XRD diffraction and friction wear test were performed to evaluate the mechanical properties of coating . Results indicate that the composite film with ZrO2 nanoparticles have reduced friction coefficient with high micro hardness friction coefficient of composite film can be small as 0.16 which is much smaller than that 0.39 of none composite film. Micro hardness... 

The main purpose of this research is design and manufacture of nanostructured hydroxyapatite-coated foamy core@compact shell Ti-6Al-4V bone-like composites for utilization as substitutive implant for cortical bone having porous core. The production procedure consist of two steps; (a) fabrication of foamy core@compact shell Ti-6Al-4V alloy using powder metallurgy-space holder technique, (b) precipitation of hydroxyapatite on the Ti-6Al-4V alloy specimens via pulse electrodeposition process. The bone-like structures were designed to reduce the stress shielding which ensures long-term stabilization of implants. It is while that, the hydroxyapatite coating improve the biological response of... 

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... 

By consideration of increasing demands to use implants and efforts to get technical knowledge and localization of this implants, considerable research in this field is needed. Therefore, presentation of a coating which is able to provide parameters needed for an acceptable implant is the aim of this study. In this direction, modification of surface of metallic implants in order to achieve nanotubes of titanium oxide, with the purpose of providing biocompatibility was done. On the other hand, because chronic infection of the implant’s surrounding is one of the main important reasons in rejection of implants, 〖TiO〗_2 nanotubes as a drug carrier were used in order to solve this problem. So,... 

In this study, biocompatible ceramic coating, containing hydroxyapatite particles (HA), was successfully created by AC anodizing, on the surface of commercially pure titanium grades 2. Coating process basically consisted of three methods. In Method 1, samples were anodized in a salty electrolyte containing calcium – phosphate base and in method 2 samples were anodized as initial process, following cathodic polarisation deposition of HA particles. Finally in method 3, samples were anodized in an electrolyte containing of HA particles suspension.Parameters such as current density and time of anodizing process, in first procedure, and time of cathodic deposition process in second procedure, and... 

Due to the technology advancement and the large-scale application of lithium-ion batteries in recent years, the market demand for lithium is growing rapidly and the availability of land lithium resources is decreasing significantly. As such, the focus of lithium extraction technologies has shifted to water lithium resources involving salt-lake brines and sea water. The ion exchange process is a promising method for lithium extraction from brine and seawater having low concentrations of this element. Among various aqueous recovery technologies, the lithium ion-sieve (LIS) technology is considered the most promising one. This is because LISs are excellent adsorbents with high lithium uptake... 

In recent decades, due to the significant growth of implants’ application and considering the infection of the implants as the most momentous factor in implantation failure, study on the controlled drug release and other biologically active agents in modern drug delivery systems has attracted many kinds of research throughout the world and efforts are being made to use regulated drug delivery systems for implantation which is also the purpose of this current scientific work.To achieve this, the anodizing process was used to fabricate titanium oxide nanotubes (TNTs) to increase the absorption capacity of the drug in the implants and these TNTs were formed regularly and uniformly in an organic... 

This dissertation argues that bi-conductive textured surfaces increase both Critical Heat Flux (CHF) and Heat Transfer Coefficient (HTC) simultaneously. Surface modification is applied to stainless steel specimens by the anodizing method in an electrolyte containing Ammonium Fluoride and DI-Water and Ethylene Glycol as the based solvent. The process of oxidation was under constant DC voltage and constant temperature. The contact angle on self-aligned Nano-porous oxide layer fabricated on the substrate substantially decreases to about 5.7 degree which has a dramatic effect on CHF. Furthermore, the oxide layer augments the boiling efficiency by increasing the number of active sites and... 

Today, recycling lithium as a valuable metal from brine plays an important role in various applications such as battery manufacturing, computers, aerospace and automobiles. Among the aqueous methods available for the extraction of the lithium element in brines, ion exchange by TiO2 nanosorbents is one of the most efficient methods. In this study, first the titanium dioxide nanotubes were well synthesized by anodizing method and the nanograss created after the anodizing process were completely eliminated. Then, the effect of three cathodes of aluminum, graphite and stainless steel in order to select the best cathode and achieve a regular morphology as well as their replacement with platinum... 

According to human needs and in line with the development of advanced technologies, different biomedical Engineering fields like hard tissue implants are growing rapidly. Despite significant biotechnology Developments in recent years, some problems to the recognition of implants related osseointegration phenomena persist. The deficient osseointegration and implant-associated infections are key issues for the long-term clinical success of titanium and titanium alloy implants, while development of multifunctional surfaces that can simultaneously overcome these problems remains highly challenging. Therefore, the ultimate goal of this paper was to improve bone cell attachment and simultaneously... 

Ice formation upon various surfaces could lead to many industry problems and result in unpleasant accidents. For instance, the formation of ice on wind turbine blades or airplanes/helicopter wings could cause catastrophic disasters. The methods used to address this problem usually require exogenous energy consumption or anti-ice ingredients. The energy or anti-ice ingredients usage has adverse environmental effects and should be replaced with better approaches. One of these approaches is utilizing modified anti-ice surfaces. In this method, by modifying surface features, such as physical asperities and surface energy, the icing time of the surface could be prolonged. These surfaces are...