Papers by Keyword: TiO₂ Coating

Abstract: Ultra-high Molecular Weight Polyethylene (UHMWPE) is a highly versatile polymer known for its exceptional mechanical properties, however, its limited life as an implant material for Total Joint Replacement (TJR) necessitates surface modification to extend its lifespan. This study aims to enhance the surface properties of UHMWPE through application of ceramic coatings. Magnetron sputtering method was used to deposit thin film of white Titania (TiO₂) on the material’s surface. To evaluate the surface characteristics, such as surface roughness, uniformity and structure, coated and uncoated samples were analyzed through Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and X-ray Diffraction Analysis (XRD). The material performance in relation to biological context was investigated through Contact Angle measurement. A comparative analysis of coated and uncoated samples was then performed. The coated samples showed better wettability compared to uncoated sample. This fact highlights the hydrophilic nature of film. The results of the coated UHMWPE suggest that this surface modification technique could significantly extend the lifespan of UHMWPE implants in TJR, potentially addressing the current limitations associated with their longevity.

Abstract: Titanium dioxide (TiO₂) is the one of photocatalyst materials that widely used for decolorization of organic compounds in wastewater by photocatalytic mechanism which can be activated by UV light. Unfortunately, in the case of fine TiO₂ power, filtration of the powder after water treatment process is difficult. In this research, coating or immobilizing the TiO₂ powder on substrates using for removing the color of lignin concentration is interesting. The objectives of this research are to prepare the floating porous cylindrical tube substrates composed of zeolite NaA and ball clay, and then to determine the efficiency of lignin degradation. Zeolite NaA powder, Suratthani ball clay and organic binder solution were mixed before extruding and cutting to be 1.5 cm diameter cylindrical tube with 2.5 cm in length and 0.3 cm in thickness. After that, the dried tubes were fired at 650 - 800 °C for 2 hours and were then coated with TiO₂-P25 suspension before re-firing at 600 °C for 1 hour in an electrical furnace. The fired uncoated tubes were characterized in terms of phase composition, porosity and radial crush strength. From the XRD pattern of the tubes fired at 800 °C showed that the zeolite NaA phase was disappeared. On the other hand, the zeolite NaA phase was found in the samples fired at another lower temperature. For the coated tubes, polyurethane foam was filled into the hole to make the tubes can be floated on the water surface. After that, the photocatalyst degradation property by determining the decreasing of concentration of lignin solution under tungsten lamp irradiation of the floated tubes were tested.

Abstract: The deposition of titanium dioxide, TiO₂, films on various substrates was studied in order to take benefit of its antimicrobial properties for suitable application in related fields. In this paper, the effect of Degussa P25 (a commercial TiO₂ nanoparticles additive in the sol) on the morphology, thickness and crystallinity of the deposited TiO₂ was investigated. TiO₂ films, without and with Degussa P25, were deposited on glass slides and unglazed ceramic tiles via sol-gel process. Films were deposited ten times using dip coating technique and heat treated at 500°C for 1 hour. The coating morphologies and thickness were analyzed using Scanning electron microscope (SEM), while the crystalline phases were characterized using Glancing angle X-ray Diffraction (GAXRD). Results show that the addition of Degussa P25 produces coating with homogeneous morphology and less cracks, thicker film and promotes the presence of anatase and rutile phases. It was also observed that the deposition of TiO₂ with Degussa P25 on unglazed ceramic tile produced thicker film (~120mm) as compared to the film deposited on glass slide (~7mm). Thus, it can be concluded that the addition of Degussa P25 affect the morphology, thickness and crystallinity of the TiO₂ coatings, whereas the type of substrate only affects the coating morphology and thickness, but not the crystallization of the TiO₂ coating.

Abstract: Titanium oxide, (TiO₂), can exist in three distinct crystallographic phases known as anatase, rutile, and brookite. Brookite, however, is the least known TiO₂ phases and usually exists as byproduct during synthesising rutile or anatase. Therefore, in this study, the influence of sol-gel pH and soaking time on surface morphology, phases and grain size of TiO₂ coating were investigated in an attempt to develop brookite thin film. Titanium (IV) isopropoxide (TTiP) is used as precursor for preparing TiO₂ sols. Prior to heating, TiO₂ layers were deposited on a glass slide by dipping it five times into TiO₂ sols. The TiO₂ layers were then heated at 450°C and soaked for 1 and 3 hours to form TiO₂ coating. Analysis on the phases and grain size were carried out using X-ray diffraction (XRD). The TiO₂ surface morphology was investigated using Scanning Electron Microscope (SEM). Results showed that brookite phase with grain size of 27.40 nm successfully deposited on glass slide from sols with pH¹². Conversely, the TiO₂ coatings deposited from sols of pH¹ and pH⁷ are amorphous. The effect of soaking time on phases and grain size is insignificant but enhances coatings uniformity as the soaking time increased. Thus, it can be concluded that sol-gel pH affect TiO₂ crystallinity and phases. Brookite film is develop only when the TiO₂ sols is in bases condition or at higher pH value.

Abstract: Plasma spray technique is used to produce coatings with excellent hardness, wear resistance and strong adhesion. TiO₂ coatings were prepared by plasma spraying at low plasma power.TiO₂ powder with anatase phase structure was used to prepare the coatings. The effect of plasma spraying parameters on the microstructure and mechanical properties of the coatings were investigated. The microstructure of the coatings showed that the coatings were formed by fully and partially melted particles. The coatings dominant phase is rutile and only a few coatings contained traces of anatase phase. The hardness and adhesion strength of the coatings were tested using Vickers microhardness and pull-off adhesion tester. The adhesion strength obtained was between 10-20 MPa and the microhardness result is between 300 - 800 Hv. The spraying parameters such as input power, spraying distance and plasma gas ratio influenced the properties of the produced coatings.

Abstract: The deposition of titanium dioxide, TiO₂, films on ceramic tiles was studied in order to take benefit of its antimicrobial properties for suitable application in related fields. In this paper, the characteristics of TiO₂ coating deposited on unglazed ceramic substrates with high surface roughness were investigated. TiO₂ films were deposited several times via dip coating sol-gel technique and heat treated at 500oC for 1 hour. The coating morphologies and thickness were analyzed using Scanning electron microscope (SEM), while the crystalline phases were characterized using Glancing angle X-ray Diffraction (GAXRD). Results show that it produces coating with homogeneous morphology, thicker film and with the presence of anatase and rutile phases. It was also observed that one dipping time is sufficient to produce a continuous coating with thickness of ~ 12 μm on average.

Abstract: In the present work formation of macro-size TiO₂ nanofiber layers in microwave synthesis were studied. Anatase nanopowder and 10M KOH solution were used as raw materials. Microwave assisted synthesis method permitted to obtain TiO₂ nanofibres containing individual nanowires with a diameter of 5nm and a specific surface area up to 129m²/g. Macro size layer of TiO₂ nanofibers was obtained on the surface of microwave vessel. Total surface area covered with TiO₂ was about 390cm². Modification with platinum allows to increase photocatalytical activity of TiO₂ macro size fiber layer up to 94.4% in UV irradiation and up to 11.6% under visible light irradiation.

Abstract: Acidic TiO₂ solutions were prepared via sol-gel using hydrochloric acid (HCl) as catalyst for TiO₂ coating deposition. The correlation between the HCl content and ageing time with the stability of the solutions was determined by controlling the content of HCl used (0.2, 0.5, 1.0 and 1.7 ml). The stability was evaluated by observing the pH and physical changes that occurred during 30 days of ageing time. The influence of HCl content on the morphology of TiO₂ thin film is further studied by depositing the films on commercialized unglazed ceramic tiles via dip-coating technique. Results of the ageing experiment showed that the PH of the solutions was stable throughout the ageing period. However, significant physical changes occurred only during the first seven days of the ageing period. Energy dispersive X-ray (EDX) analysis disclosed that the TiO₂ coatings were distributed unevenly on the substrate surface creating multilayers of coating. Scanning electron microscope (SEM) micrographs suggest that the TiO₂ solution prepared using 0.5ml of HCl (pH 1.0 – 1.5) produces better TiO₂ coating performance due to less amount of cracks and more homogeneous coating than other HCl content solutions.

Abstract: Iron foam is a type of material having potential to be used as water or air filter andimplant material. One of the limitations of this material is its high reactivity on corrosion. In thepresent research TiO2 coating on iron foam substrate has been developed by self-assembledmonolayer method. Focus is given on the effect of TiCl4 and chitosan concentration on thecharacteristic of the developed TiO2 layer. Precursor was prepared with HCl concentration of 0.5; 1;1.5 M and chitosan solution concentration of 1% ; 2% ; 4% (w/v). Scanning Electron Microscopy(SEM) and Energy Dispersive Spectroscopy (EDS) characterizations show that TiO2 particles areformed on the iron foam surfaces. It was observed that with the higher TiCl4 concentration moreTiO2 particles obtained on substrate surfaces. On the other hand, SEM results also show the averageTiO2 particles size at around 1 micrometer and in tetragonal shape. It was observed that with thehigher chitosan concentration, the particles shape tend to have tetragonal stucture, while at lowerchitosan concentration (1%), agglomeration of TiO2 particles were observed.

Abstract: In this paper, a Li-rich cathode material Li_1.2Mn_0.6Ni_0.2O₂ is modified by the nanoscale TiO₂ coating using a simple and controllable hydrolyzation method. The effect of nanoscale TiO₂ coating on the bulk structure, surface morphology and electrochemical performance are characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and electrochemical techniques, respectively. The results show that the nanosize TiO₂ can be well coated on the surface of the cathode material. The coating layers have no influence on the bulk structure of the cathode material, while they can improve the initial discharge capacity, columbic efficiency and cycling performance.