Sharif Digital Repository

Silver-doped indium tin oxide thin films were synthesized using sol-gel dip-coating technique. The influence of different silver-dopant contents and annealing temperature on the electrical, optical, structural, and morphological properties of the films were characterized by means of four-point probe, UV-Vis spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscope (XPS). XRD analysis confirmed the formation of cubic bixbyte structure of In2O3with silver nanoparticles annealed at 350 °C. XPS analysis showed that divalent tin transformed to tetravalent tin through oxidization, and silver nanoparticles embedded into ITO... 

In this report, crack-free nanostructured barium titanate thin films are prepared by a sol-gel processing method. Glacial acetic acid, barium acetate, titanium tetraisopropyl alkoxide, 2-propanol and deionized water are used as precursors for preparing stable precursor solution. Then very thin films (thickness=26 nm) are deposited on fused silica substrates. In order to prepare crack-free thin films of BaTiO3, much attention is given to solvent evaporation process and a controlled pre-drying process is developed. It is found that the control of the process, especially in the initial stage of drying process is crucial and important for preparation of the crack-free ultrathin nanostructured... 

A recently developed two-level undercut-profile substrate (2LUPS), containing two levels of plateaus connected by a curved wall with an undercut profile, enables self-forming filaments in a coated conductor during physical line-of-sight deposition of buffer and superconducting layers. In the present study, the 2LUPS concept is applied to a commercial cube-textured Ni-5at.%W tape, and the surface of the 2LUPS coated with two Gd2Zr2O7 buffer layers using chemical solution deposition is examined. Except for narrow regions near the edge of upper plateaus, the plateaus are found to be covered by strongly textured Gd2Zr2O7 buffer layers after dip coating and sintering  

The influence of annealing temperature on the hydrophilic property of WO3 thin films deposited by thermal evaporation and sol-gel dip-coating methods was studied and compared for the first time. The thermal evaporated WO3 thin films annealed at 400 °C showed a nearly super-hydrophilic property without UV and visible illumination. By analysing the O(1s) core level peak of XPS spectra, the amount of oxygen contributed at various bonds (including O2-, OH- and H2O) on the surface of the annealed samples at different temperatures were measured. In addition, a correlation between the hydrophilicity and the concentration of chemisorbed water on the film surface was suggested, independent of the... 

(Lanthanum, Cerium)(Iron, Manganese, Cobalt, Palladium)(Oxygen)3- Perovskite catalyst was prepared by the citrate route and deposited on ceramic monoliths via dip coating procedure. The catalyst was applied on a car with XU7 motors and the amount of emission was monitored with vehicle emission test systems in Sapco company. The results were compared with the imported catalyst with noble metals such as palladium, platinum and rhodium by Iran Khodro company based on the Euro III standards. The catalysts were characterized by specific surface area measurements, scanning electron microscopy, X-ray diffraction, line scan and map. In the results, obtained in the home made sample, the amount of... 

TiO2/multi-wall carbon nanotube (MWNT) heterojunction arrays were synthesized and immobilized on Si(0 0 1) substrate as photocatalysts for inactivation of Escherichia coli bacteria. The vertically aligned MWNT arrays were grown on ∼5 nm Ni thin film deposited on the Si by using plasma enhanced chemical vapor deposition at 650 °C. Then, the MWNTs were coated by TiO2 using dip-coating sol-gel method. Post annealing of the TiO2/MWNTs at 400 °C resulted in crystallization of the TiO2 coating and formation of Ti-C and Ti-O-C carbonaceous bonds at the heterojunction. The visible light-induced photoinactivation of the bacteria increased from MWNTs to TiO2 to TiO2/MWNTs, in which the bacteria could... 

In this investigation, sol-gel synthesized nanoporous silica thin films, annealed at different temperatures, with long time superhydrophilic property have been studied. Two kinds of sol-gel silica thin films were fabricated by dip-coating of glass substrates in two different solutions; with low and high water. The transparent coated films were dried at 100 °C and then annealed in a temperature range of 200-500 °C. The average water contact angle of the silica films prepared with low water content and annealed at 300 °C measured about 5° for a long time (6 months) without any UV irradiation. Instead, adding water into the sol resulted in silica films with an average water contact angle... 

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... 

Post-deposition annealing effects on nanomechanical properties of granular TiO2 films on soda-lime glass substrates were studied. In particular, the effects of Na diffusion on the films' mechanical properties were examined. TiO2 photocatalyst films, 330 nm thick, were prepared by dip-coating using a TiO2 sol, and were annealed between 100 °C and 500 °C. Film's morphology, physical and nanomechanical properties were characterized by atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, differential thermo-gravimetric analysis, and nanoindentation. Contrary to expectations, the maximum film hardness was achieved for 300°C annealing, with a value of 0.69 ± 0.05 GPa.... 

Thin films of titanium dioxide with high surface area are prepared by sol-gel dip-coating technique. In this regards, Titania nano sols with high photocatalytic activity were prepared by dissolving titanium alkoxide in alcohol and water under acidic conditions. Photocatalytic activities of titanium dioxide thin films were measured in the presence of methylene blue. Microstructure and photocatalytic activity of the films, nanopowders and titanium dioxide sols were investigated using X-ray diffraction, scanning electron microscopy, specific surface area, zeta sizer and ultraviolet-visible spectrometry techniques. Particle size analysis of sols showed that the mean particle sizes were 15 to 128... 

In this study hydroxyapatite (HA)/zirconia/alumina composite coatings on titanium metal was carried out using Sol-Gel dip coating and calcination process. Hydroxyapatite-Alumina-Zirconia sol, coated samples in three processes by changing final sol stirring time, aging time, calcination temperature of synthesized powder and prepared coating and rate of coating. Some parts of prepared sol were also synthesized and became powder in all three processes. Scanning electron microscopy was used to estimate the particle size of the surface and for morphological analysis. The functional group and crystallization characteristics of the powders were analyzed using (FTIR) and X-Ray diffraction (XRD).... 

A hydrogen-selective nano-composite ceramic membrane was prepared by depositing a dense layer composed of SiO2 and Al2O 3 on top of a graded multilayer substrate using co-current chemical vapor deposition (CVD) method. The multilayer substrate was made by dip-coating a macroporous α-alumina tubular support by a series of boehmite solutions to get a graded structure. Using DLS analysis, it was concluded that decreasing hydrolysis time and increasing acid concentration lead to smaller particle size of boehmite sols. XRD analysis was carried out to investigate the structure of intermediate layer and an optimized calcination temperature of 973 K was obtained. SEM images indicated the formation... 

The low erosion resistance of titanium and its alloys has prevented their widespread application as joint implants. In addition, one essential requirement for the implants to bond with the living bone is the formation of a bone-like apatite on their surfaces in the host body. To enhance the erosion resistance of the surface, a diffused layer of TiB2 was formed at 1000uC on the commercial pure titanium. Hydroxyapatite was then coated on the boronised titanium by means of dip coating in a sol-gel solution. In order to confirm the biocompatibility of the specimens, they were soaked in a simulated body fluid for several days. The surface morphology of the specimens after exposure was studied by... 

Research and development efforts continue to improve oxidation resistance and electrical conductivity of solid oxide fuel cell (SOFC) interconnects. This research evaluates the performance of a ferritic stainless steel (AISI 430 - a candidate SOFC interconnect material) with and without a Co coating (via sol-gel dip coating technique) with various pre-treatments, during cyclic oxidation exposures up to 750°C in laboratory air. A pre-treatment exposure of Co coated samples to a 750°C reducing atmosphere (prior to oxidation exposures) led to the formation of an effective Co-based spinel oxide coating that lowers oxidation rates by more than 40 times, and substantially lowers area specific...