Papers by Keyword: Anatase

Abstract: The possibility of production of white cover glass-enamel coatings for steel products has been considered. A number of compositions of glass-enamel coatings has been worked out. The obtained samples have been subjected to tests for corrosion resistance, temperature resistance and whiteness index. The peculiarities of crystallization in white cover glass-enamel coatings have been revealed. It is shown that the produced cover glass-enamel coatings for steel products conform to all requirements of GOST R 52569-2006. The application of RGB color model has been considered to determine the color hues of the white enamel coatings.

Abstract: Electrochemical dispersion method for producing of TiO₂ nanoparticles in anatase form has been proposed. It was found that the ratio between the current density of the anodic and cathodic pulses has an impact on the specific surface area (90–155 m² g^-1) and particles size (≈10-14 nm) of prepared TiO₂ powders was but doesn’t impact on the products composition. The electrolyte concentration doesn’t impact on the rate of Ti electrode dispersion as well as TiO₂ powders morphology.

Abstract: This manuscript presents the results of titanium dioxide thin films study which were produced from organotitanium precursor films by thermal treatment or UV radiation. The organotitanium precursor films were deposited on a glass or foil substrate by centrifugation. XRD and AFM measurements confirmed the formation of well-crystallized titanium dioxide films with anatase structure at temperature of 400°C. The study of the surface morphology of anatase films showed the formation of surface with crystallographic indices (101). The choice of amorphous and crystalline titanium dioxide thin films for XRD analysis was experimentally justified.

Abstract: Titania (TiO₂) is one of a common and favorable material use in the manufacturing industry due to its uniqueness and functional performances to human and environment. The study was focused on the performance of glaze added TiO₂ (anatase phase) in the application of porcelain tiles. Anatase powder in micro size was used (varies at 5 wt%, 10 wt % and 15 wt%) to observe their performance as antibacterial materials. The anatase powders were mix into the glaze composition and apply to the porcelain tile through dip coating. The viscosity of each composition was observed to study their effect. Characterization used to observe the properties of anatase mixed glazed porcelain tile were X-ray diffraction (XRD), Scanning electron microscopy (SEM) and antibacterial test. The results shown that higher composition of anatase powder, viscosity of the mixed glaze is higher and a rougher surface of glazed tiles was formed. XRD result shows that the higher the composition is more the intensity of TiO₂ on the glaze coating surface, supported by SEM results. Antibacterial testing towards E.Coli was observed by counting the colonies of bacterial growth in 0 hr, 2 hrs, 4 hrs and 8hrs. The antibacterial properties increase when the composition of anatase increases.

Abstract: Titanium (Ti) is widely used in dental and orthopedic implants because of its good biocombatibility and high corrosion resistance. Titanium oxide (TiO₂) has shown to exhibit strong physicochemical bonding between Ti implant and living bone because of its ability to induce bone-like apatite in a body environment. Ti is always coated by an oxide surface layer of 1.5-10 nm thickness. TiO₂ crystalline structures; anatase and rutile present several distinctive features, such as photocatalytic behaviour, superhydrophilicity and biocompatible properties. Anodic oxidation is used to modify the surface of pure titanium in a phosphuric acid electrolyte in order to maximize and characterize the TiO₂ anatase crystalline phase. In the present work, thick films of the anatase polymorph of TiO2 were formed on commercially pure Ti foil under potentials 200 V-350 V at current densities 40 and 60 mA/cm² for 10 min. Multiple characterization techniques were used. Glancing angle X-ray diffraction (GAXRD) is used to obtain crystalline phases, field emission scanning electron microscope (FESEM) is used to obtain surface images and water contact angle (WCA) is used to obtain the wettability of the oxide surface. According to GAXRD results the intensity of the major peak increased with increasing applied voltage and current density while decrease with molar concentration. This means that the amount and/or crystallinity of anatase are/is influenced with these parameters. The coated oxides obtained small amount of anatase is comparing to films anodized in H₂SO₄ electrolyte. Which confirm that slower crystallization in H₃PO₄ than in H₂SO₄. FESEM images obtained that as the voltage increased, the film breaks down locally and results in a porous surface. The porosity and the pore size increase with the increasing voltage. The pore size diameter at 300V for 0.3 M can reach up to 1μm. As for WCA results the coated samples at higher voltages (250 V, 300 V and 350 V) and molar concentration 0.3 M have shown more hydrophilic surface, with sample anodized at 350 V at 0.3 M have the lowest contact angle, thus the highest surface energy. While samples anodized at 200 V voltage observed more hydrophobic surface with sample anodized at 200 V at 0.1 M have the lower wettability, thus the lowest surface energy.

Abstract: Titania with a mixture of anatase, rutile and brookite nanostructures have gained much attention lately due to their high photocatalytic activity. Pure titania (TiO₂) with a mixture of anatase, rutile, brookite phase were synthesized by hydrothermal treatment using titanium isopropoxide (TTIP) and 1.0 M of urea. The titania were doped with 1wt% of single transition metal nickel (Ni), vanadium (V) and manganese (Mn) and 1 wt% bimetallic transition metal of Ni-V and Ni-Mn, respectively. Pure titania shows higher, 94 % degradation of ibuprofen (Ibp) as the presence of brookite phase in the structure. The band gap energy of titania was obtained using the Kubelka-Munk reflectance function decreased as doping a transition metallic dopant where the energy order are V<MN<Ni, respectively. Bimetallic dopant V and Mn contribute higher photocatalytic activities as decreasing band gap energy of Ni ion doping.

Abstract: Titanium (Ti) is widely used in dental and orthopedic implants because of its good biocombatibility and high corrosion resistance. Titanium oxide (TiO₂) has shown to exhibit strong physicochemical bonding between Ti implant and living bone because of its ability to induce bone-like apatite in a body environment. Ti is always coated by an oxide surface layer of 1.5-10 nm thickness. TiO₂ crystalline structures; anatase and rutile present several distinctive features, such as photocatalytic behaviour, superhydrophilicity and biocompatible properties. Anodic oxidation is used to modify the surface of pure titanium in a sulphuric acid electrolyte in order to maximize and characterize the TiO₂ anatase crystalline phase. In the present work, thick films of the anatase polymorph of TiO2 were formed on commercially pure Ti foil under potentials 100V-140V at current densities 40 and 60 mA/cm² for 10 min. Multiple characterisation techniques were used and found that the maximum level of significantly formed anatase intensity where no significant rutile formation is observed at potential 140 V according to Glancing angle X-ray diffraction (GAXRD). Field Emission Scanning Electron Microscope (FESEM) images have shown porous surfaces as the applied voltage increased. Water contact angle (WCA) values observed hydrophilicity on the coated surfaces with samples anodized at 120 V have the highest wettability.

Abstract: Titanium oxide (Ti-O) films were prepared by low-voltage (i.e., 5-15 V) anodization of titanium plate in different hydrochloric acid (HCl) concentrations. Phase composition and surface microstructure of the anodized sample were investigated through XRD and SEM characterizations. Samples anodized at 15 V and in 0.6, 1.5 and 3.0 M HCl concentrations show higher amount of crystalline TiO₂ (i.e., anatase and rutile) phases as compared to other anodizing conditions. The three samples show open pores microstructure on the anodized surface. Samples anodized at lower voltages and in low to medium HCl concentrations also produce loosely bonded amorphous Ti-O granules on top of the crystalline TiO₂ phases. After annealing these samples at 400 or 600°C in air, further oxidation occurred on the anodized surface particularly at pores, contribution to slight increase in the crystalline phase. It suspected that the presence of amorphous Ti-O granules on top of crystalline TiO₂ phases at initial anodizing stage, hindered movement of OH^- and Cl^- anions onto the anodized surface, thus inhibited further growth of the crystalline TiO₂ phases.

Abstract: Phase transformation of TiO₂ (titanium dioxide) nanoparticles has been analyzed by observing the effect of NaCl addition to the anatase-to-rutile phase transformation. NaCl is one of key points in the transformation of rutile. Co-precipitation method was employed in which TiCl₃ as precursor was reacted with HCl 2M and subsequent NH₄OH. Three methods were studied, namely solution without NaCl addition (TiCl₃ + HCl + NH₄OH) as control solution subjected to route A (TiCl₃ + HCl – NaCl– NH₄OH – heated at 600°C for 5 hours) and route B (TiCl₃ + NaCl – heated 200°C for 5 hours – NH₄OH – heated 200°C for 6 hours). Route B was subjected to heating at 200°C. The results show that without NaCl it enhanced the crystal growth of the rutile embryos allowing the ease of rutile formation at 600°C, while route A promoted the transformation of brookite and hindered anatase-to-rutile transformation as indicated by the presence of anatase at 1000°C. On the other hand route B is potential for being further explored.

Abstract: In this study, TiO₂ nanoparticles were successfully synthesized using sol-gel technique by employing different mixing routes. The nanoparticles were characterized for field emission scanning electron microscopy, energy dispersive X-Ray spectroscopy, Fourier transformed infrared, Raman spectroscopy, x-ray diffraction and ultraviolet visible spectroscopy. It is apparent that different mixing sol-gel route significantly influenced the morphology, crystallite structure, particle and crystal size and band gap of TiO₂, under similar molar ratio. The differences in physicochemical and optical properties of synthesized TiO₂ greatly influenced its photocatalytic activity in reactive black 5 dye degradation. In overall, mixed crystal structures of anatase and rutile showed better photocatalytic activity for the degradation of reactive black 5 dye due to a narrower band gap, as opposed to single phase TiO₂.