WO3 as Additive for Efficient Photocatalyst Binary System TiO2/WO3

Two different methods of synthesis of TiO2/WO3 heterostructures were carried out with the aim to increase photocatalytic activity. In this study, anodic TiO2 nanotube films were synthesized by electrochemical anodization of titanium foil. WO3 particles were applied to anodic Ti/TiO2 samples in two different ways – by electrophoretic deposition (EPD) and insertion during the anodization process. Structural and photocatalytic properties were compared between pristine TiO2 and TiO2 with incorporated WO3 particles. Raman mapping was used to character-ise the uniformity of EPD WO3 coating and to determine the structural composition. The study showed that deposition of WO3 onto TiO2 nanotube layer lowered the band gap of the binary system compared to pristine TiO2 and WO3 influence on photo-electrochemical properties of titania. The addition of WO3 increased charge carrier dynamics but did not increase the measured photo-current response. As the WO3 undergoes a phase transition from monoclinic to orthorhombic at approximately 320 ℃ proper sequence WO3 deposition could be beneficial. It was observed that secondary heat treatment of WO3 lowers the photocurrent.

Supercapacitor electrodes based on modified titania nanotube arrays on flexible substrates

Highly ordered titania nanotube arrays were synthesised on titanium metal foil through electrochemical anodisation. The annealed samples were characterised through scanning electron microscopy and X-ray diffraction analysis. The electrochemical characterisations of the arrays were done through cyclic voltammetry, galvanostatic charge discharge and electrochemical impedance spectroscopy analyses. The titania nanotube arrays exhibited a specific capacitance of 6.8 mF cm–2 at 5 mV s–1 scan rate, which is very much higher than that reported earlier. Pseudocapacitive metal oxides were deposited on these arrays forming composite supercapacitor electrodes and their supercapacitor properties were compared with same deposited on bare titanium foil substrates. Pseudocapacitive metal oxides deposited on these titania nanotube array substrates exhibited improved supercapacitor performance and stability over the same deposited on titanium foil substrates.

The Role of Blood Clot in Guided Bone Regeneration: Biological Considerations and Clinical Applications with Titanium Foil

In Guided Bone Regeneration (GBR) materials and techniques are essential to achieve the expected results. Thanks to their properties, blood clots induce bone healing, maturation, differentiation and organization. The preferred material to protect the clot in Guided Bone Regeneration is the titanium foil, as it can be shaped according to the bone defect. Furthermore, its exposition in the oral cavity does not impair the procedure. We report on five clinical cases in order to explain the management of blood clots in combination with titanium foil barriers in different clinical settings. Besides being the best choice to protect the clot, the titanium foil represents an excellent barrier that is useful in GBR due to its biocompatibility, handling, and mechanical strength properties. The clot alone is the best natural scaffold to obtain the ideal bone quality and avoid the persistence of not-resorbed granules of filler materials in the newly regenerated bone. Even though clot contraction still needs to be improved, as it impacts the volume of the regenerated bone, future studies in GBR should be inspired by the clot and its fundamental properties.

About the titanium foil using in the brazed construction of small windows for the transmission of radiant energy

The aim of this work was to miniaturize the design of a brazed joint of a thin non-metallic disk with a hollow thin-walled metal cylinder for operation as part of a vacuum device in a wide temperature range. For brazing a non-metallic disk with a glass tube-shaped device body, when choosing a metal filler, the fragility of glass, its low mechanical strength in bending and tensile and a lower thermal coefficient of linear expansion than metal fillers must be taken into account. Therefore, the use of low-temperature plastic solders based on tin, indium, lead etc., which are alloyed with titanium, is preferable. However, the disadvantages of these fillers include a significant decrease in mechanical strength when the brazed unit is heated to relatively low temperatures, especially if there is a gas inside the device under excessive pressure. The option of brazing a leucosapphire disk with a glass tube was also considered. A design has been proposed to determine how a disk is connected to a titanium body. This design has increased the heat resistance of the leucosapphire lens, which is connected to the body of the product made of titanium alloy or covar. Such connection can be used as pyrometer windows installed directly in the body of an internal combustion engine or gas turbine engine. The main feature of this development was the creation of a brazed joint structure in which the shell covering the disk is made of non-metal, in this case of leucosapphire, made of titanium foil with a thickness of 100 and in some cases 50 μm. Brazing modes were set and brazed windows were made. Tests on the vacuum density after different modes of thermal cycling of brazed samples showed high performance of this structure of the brazed joint. It was shown that the use of titanium foil makes it possible to obtain high-quality heat-resistant brazed joints. The relatively small stresses that lead to plastic deformation of the foil make it possible to increase the inconsistency of the thermal coefficient of linear expansion (TCLE) of materials that were brazed. It shout be noted that the foil material can also be other metals which had chemical active towards non-metallic materials or their components, for example, zirconium, niobium, tantalum, etc. Keywords: structures of brazed joints, brazing of non-metals, non-metallic materials, leucosapphire, glass tube, adhesive-active filler metals, fillers, titanium.

Water-Jet Cavitation Shock Bulging as Novel Microforming Technique

With the continuous expansion of the application range of microelectromechanical systems, microdevice forming technology has achieved remarkable results. However, it is challenging to develop new microforming processes that are low cost, environmentally friendly, and highly flexible; the high-energy shock wave in a cavitation bubble’s collapse process is used as the loading force. Herein, a new process for the microbulging of the water-jet cavitation is proposed. A series of experiments involving the water-jet cavitation shock microbulging process for TA2 titanium foil is performed on an experimental system. The microforming feasibility of the water-jet cavitation is investigated by characterizing the shape of the formed part. Subsequently, the effects of the main parameters of the water-jet cavitation on the bulging profile, forming depth, surface roughness, and bulging thickness distribution of TA2 titanium foil are revealed. The results show that the plastic deformation increases nonlinearly with the incident pressure. When the incident pressure is 20 MPa, the maximum deformation exceeds 240 μm, and the thickness thinning ratio changes within 10%. The microbulging feasibility of water-jet cavitation is verified by this phenomenon.

Фазовый переход первого рода в нанотубулярном диоксиде титана

Titanium dioxide (TiO2) nanotubes array with the length of 16 μm and the outer diameter of 100 nm were synthesized by anodic oxidation of titanium foil in an electrolyte solution containing a fluorine-containing solution of ethylene glycol. The selected synthesis conditions make it possible to separate the nanotubular array from the titanium foil and study it as a homogeneous functional material. The performed scanning electron microscopy study and Brunauer–Emmett–Teller analysis allowed to get data on the morphology of the samples. X-ray diffraction, thermogravimetric, and differential scanning calorimetry analysis made it possible to determine the temperature of the phase transition of the amorphous state into crystalline anatase (sp.gr. I4/amd). Observed phase transition of first order takes place at temperature about 350 °С.