Papers by Keyword: Titanium Oxide

Abstract: Abstract. This studies discuss the synergistic effects of titanium dioxide (TiO₂) and zinc borate on thermal stability and water resistance of intumescent fire retardant coatings. TiO₂ in association with a traditional intumescent flame retardant system which contains ammonium polyphosphate/expandable graphite/melamine/ zinc borate (APP–EG–MEL-ZB) was introduced to epoxy based coatings to improve the fire resistance. The influences of TiO₂ on the properties of the coatings were investigated in detail by using Bunsen burner fire test, thermogravimetric analysis (TGA), scanning electron microscope (SEM) and water immersion test. Bunsen burner test revealed that incorporation of titanium dioxide in intumescent formulation reduced the steel substrate temperature from 240 °C to 116 °C. The TGA results proved that addition of TiO₂ could enhance the anti-oxidation of the char layers and increase the residue weights of the coatings. The FESEM images demonstrated that addition of TiO₂ could improve the foam structure of the char residue. Sea water resistance test demonstrated that the optimum mass % age of TiO₂ (6%) exhibited great synergism with natural anti-corrosion agent, zinc borate, and improved corrosion resistance performance of intumescent coating formulations.

Abstract: The improvement of photocatalytic activity of TiO₂ has been explored. TiO₂ has been doped with some transition metal elements for new photocatalytic materials. They were prepared using nitrates of Fe, Cu and Zn. Their photocatalytic activities were investigated by conducting a semi-batch experiment. The degradation of aqueous humic acid was performed under near-visible irradiation. For examining the photocatalytic characteristics of the new materials, the dissolved organic carbon and the UV254 absorption of humic acid were analyzed. The new metal-doped photocatalysts showed higher photoactivities than the synthesized pure TiO₂. And photodegradation result of humic acid by the new metal-doped material was even better than by the commercial Degussa P-25 TiO₂ at wavelengths of 315 nm - 400 nm.

Abstract: Electrochemical disinfection device EDI-001 equipped with titanium oxide (TiO_2-x) ceramic electrodes was tested as a system for direct treatment of drinking water at flow conditions. Laboratory experiments were conducted to estimate the disinfection efficiency and main system parameters. Escherichia coli was selected as the model microorganism. The results have shown that contaminated tap water was completely disinfected within 15 minutes by using EDI-001.

Abstract: In this study, we synthesized the TiO₂-modified hydroxyapatite (HAp) with various morphologies by hydrothermal treatment using urea decomposition, at 160 oC for 6 h. After hydrothermal treatment, carbonate-substituted HAp and TiO₂ (anatase) phases were formed in products using 1.0-0.1 M urea solution. The morphology of synthesized HAp changed from small plate-shaped to long needle-shaped crystals with decreasing the urea concentration. The photocatalytic property for samples was investigated by decoloration test using 25 ppm methylene blue solution. In comparison with HAp samples without TiO₂, the TiO₂-modified HAp clearly showed the photocatalytic decomposition of methylene blue by UV irradiation.

Abstract: In this paper, Sn-0.7Cu composite containing weight percentage of 1.0 wt. % of titanium oxide (TiO₂) particles were successfully fabricated by using the powder metallurgy (PM) route assisted hybrid microwave sintering. This research investigated the effect s of TiO₂ particles addition on the interfacial reactions formed between Sn-0.7Cu solder/substrate and shear strength of a Sn-0.7Cu solder alloy. With the increasing of TiO₂ particles, Sn-0.7Cu-TiO₂ composite solder showed decreasing in thickness value and shear strength was increased. This signified that the presence of TiO₂ particles effect on the thickness of Cu₆Sn₅ IMC layer at the interface and mechanical properties Sn-0.7Cu composite solder joint.

Abstract: In this study, ionothermal synthesis process has been used for the preparation of two different types of Titania nanomaterials and that were utilized in the degradation of waste-water like (sulfan blue). The ionic liquid were used as 1-butyl-3-methylimidazolium dimethyl phosphate ([Bmim] DMP) as (TP) and 1-butyl-3-methypyridium dicyanamide ([Bmpm]DCN) as (TCN) respectively for the synthesis of anatase type Titania nanomaterials and confirmed with X-Ray diffraction pattern (XRD). The particle sizes and surface morphology were characterized by field emission scanning electron microsopy (FESEM), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET). The sizes of the particle were found to be approximately 35±5 nm from the microscopic picture analysis. The nitrogen adsorption analysis measured a surface area of 455 and 220 m² g^-1 and pore volume of 0.25 and 0.15 cm³ g^-1 for ([Bmim]DMP) and ([Bmpm]DCN) related synthesis TiO₂ nanomaterials respectively. The degradation rate of sulfan blue is higher in the presence of TP as compared to TCN owing to the larger surface area.

Abstract: In this paper it has been deposited films of titanium oxide (TiO₂), on a support of glass, by a D.C. magnetron sputtering system, by varying the working pressure (p = 2∙10^-3 - 6.5∙10^-3mbar) of the substrate temperature on three levels. The obtained layers were investigated and characterized by optical microscopy, Scanning Electron Microscopy SEM, X-ray diffraction and Atomic Force Microscopy. It was observed that, by modifying technological parameters of the process (working pressure and substrate temperature) it is changing the initial orientation of the compounds ((100) turns into (101) or (002)). The AFM analysis has allowed the observation of the fact that the average roughness of deposited films, expressed as RMS, has increased over 98% at the increasing of sputtering pressure from 2 10^-3mbar to 6.5 10^-3mbar. SEM analysis showed that the density of the deposit increases with substrate temperature. The granulation of the films obtained, presents an increasing trend with the variation of process parameters.

Abstract: Observation on the effect of adding titanium oxide (TiO₂) and magnesium oxide (MgO) on the sintering of α-alumina (Al₂O₃) has been performed. In this study, technical alumina used as basic material in which the sample is formed by the pressureless sintering/cold press and sintered at 1500°C which is lower than alumina sintering temperature at 1700°C. Elemental analysis, observation of microstructure, hardness, fracture toughness and density measurements were carried out to determine the physical and mechanical properties of alumina. The results indicate a change in the microstructure where the content of the platelet structure are much more than the equilateral structure. At sintering temperature of 1500°C, neck growth occurs at ceramics grain, supported by the results of the density test which indicate perfect compaction has occurred in this process.

Abstract: In this work, composite ceramic was produced to base Al₂O₃ reinforced with 35% weight TiO₂ and variation 0-2% La₂O₃, were evaluated properties to study their microstructural characteristic and mechanical properties as applicable cutting tools. The ceramic composites were produced by thermo-mechanical process. It was observed from the results of XRD after sintering no new phase is formed, besides the characteristics of the precursor oxides. According to the result of particle size analysis before and 24 hours after milling, there was a reduction of the average diameter of agglomerate 95.25% which is suitable to assist sintering of the composite, because this reduction increases the reaction rate the raw material during firing. At microdurezavickers test it was observed that the sample with 1.5% La₂O₃ showed better hardness results.

Abstract: This paper presents the preparation, characterisation and thermal behavior of TiO₂/water Nanofluids with different concentration. The presence of Nanosized particles in the conventional heat transfer fluids enhances its thermo physical character. In the present work, TiO₂/water Nanofluids with various volume concentrations were prepared by dispersing a specified amount of spherical sized TiO₂ Nanoparticles in distilled water without any surfactant. To get a uniform dispersion and stable suspension, the Nanofluids were kept under ultrasonic vibration continuously for 3 hours. Zeta potential measurement brought detailed insight into the causes of dispersion, aggregation of Nanofluids. The KD2 Pro, fully portable thermal properties analyser, was used to measure thermal conductivity of nanofluids. The viscosity of the nanofluid was measured using a Brookfield Viscometer. The experimental results show that the thermal conductivity increases with an increase of particle volume fraction and the enhancement was observed to be 9.22% over the base fluid for volume concentration of 0.75%. From the experimental observations, enhancement in thermal conductivity is larger than the enhancement in viscosity.