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This study reports a combined electrochemical method for preparation of a titanium dioxide–suboxide composite with an electrochemically deposited non-continuous platinum layer on the surface, which can be used for cathodic protection of metal structures. Platinum significantly modifies the properties of TiO2, stabilizes the surface, and prevents the formation of a passive non-conductive layer. The coating has significant advantages compared to Ti/Pt, traditionally used for electrochemical protection, as the platinum content in the composite is significantly reduced. Unlike a continuous precious metal layer, this method of composite formation, particularly thermal treatment in an air atmosphere at 5000 C, allows protecting the platinum, which is encapsulated in titanium oxides, and avoiding the creeping passivation typical of traditionally used materials. The surface of the coatings was investigated using X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, and X-ray microanalysis. Studies of the electrocatalytic properties, especially concerning the oxygen evolution reaction, revealed deviations of the Tafel slope from the theoretical value, which is explained by structural heterogeneity and the presence of a semiconductor component. The stability and corrosion resistance of the composites were studied. It was found that the properties remain unchanged even after prolonged exposure to a corrosive environment. [ABSTRACT FROM AUTHOR]

This study focuses on titanium dioxide (TiO2) nanotubes on solid substrates, which may find wide applications as photocatalysts and catalysts. To address the need for more stable and active electrocatalysts with reduced noble rretal content, the study explores Ti. Oj sub oxi des as promising substrates for the electrocatalysts. Notably, the addition of water in the fluoride-containing electrolyte plays a critical role in shaping the moiphology of TiO2 nanotubes, leading to the fonnation of ordered structures under specific water concentration conditions. The study also examines the effects of platinum and palladium deposition on TiO2 nanotubes, enhancing their surface crystallinity and structural arrangement. The presence of an unidentified phase, possibly titanium hydride, is observed in certain samples. The findings highlight the potential of TiO2 nanotubes as efficient electrocatalysts and the influence of water content and substrate choice on their properties, opening up new avenues for advanced applications in various fields. [ABSTRACT FROM AUTHOR]

It was found that a combination of the advantages of ultrasonic testing and electronic speckle-interferometry in the case of elimination of their disadvantages is the base for development of the method of non-destructive evaluation of residual welding stresses in full-scale structures. A procedure of non-destructive evaluation of the distribution of residual tensile welding stresses in the weld zone of a butt welded joint was developed. It is based on a simultaneous application of ultrasonic testing and electronic speckle-interferometry and fulfillment of the condition of "area equality" of the epures of balanced compressive and tensile residual stresses. The procedure was proposed for the application on specimens of single-pass welded joints of thin-sheet constructions from metallic materials with a stable structure. The subject of the study is tensile residual welding stresses in a MIG-welded specimen of a butt joint of structurally stable 1561 aluminium alloy. Residual welding stress σx component longitudinal relative to the weld was evaluated in the plate central area. It was found that the discrepancy of the values of residual welding stresses near the center of the welded joint of 1561 aluminium alloy is equal to approximately 0.1σ0.2 for this material, which corresponds to the claimed accuracy of the methods. Based on the research results, a range of procedures was proposed for the non-destructive evaluation of the residual welding stresses in full-scale welded structures, based on a combination of ultrasonic testing and electronic speckle-interferometry. [ABSTRACT FROM AUTHOR]

This work reports the optimal conditions for the synthesis of a matrix for the creation of photo- and electrocatalysts. Specifically, it is shown that TiO2 nanotube arrays has a high specific surface area and improved catalytic properties, but has low conductivity and weak structural strength, that requires further optimization. The original TiO2 nanotubes were prepared by anodizing of Ti foil in ethylene glycol with 0.3 wt.% ammonium fluoride and 2 vol.% water at a constant potential, followed by another anodizing in ethylene glycol with 5 wt.% H3PO4. The reduction was conducted in 1 M HClO4. Some samples were thermally treated in the air using tube furnace. The study demonstrates how the synthesis conditions of the coating affect the morphology and stoichiometry of the resulting oxide coating. For the obtained materials, the Tafel slope in the oxygen evolution reaction is determined by the semiconductor characteristics of the coating, which, in turn, depend on the stoichiometry of the synthesized oxide. The higher the stoichiometry in the oxygen sublattice, the fewer the charge carriers and the greater the contribution of the semiconductor component to the Tafel slope. As for hydrogen evolution, the layers obtained after heat treatment show a lower Tafel slope (175 mV dec-1). [ABSTRACT FROM AUTHOR]

Naked Ti/TiO2 contains a significant amount of X-ray amorphous compounds on the surface, which are most likely hydrated titanium oxides. The main crystalline phase is titanium dioxide in the allotropic anatase form. Metallic titanium is present on the surface in trace amounts. Thermal treatment of this material at a temperature of 500°C for 3 hours in an air atmosphere leads to an increase in the proportion of the crystalline phase. The content of metallic titanium increases significantly, reaching about a third. A partial electrochemical reduction of nanotubes allows one to obtain more electrically conductive titanium suboxides. After cathodic reduction of nanotubes for one hour, a coating with metallic platinum is uniformly deposited on the surface of the material. Thermal treated Ti/TiO2 nanotubes are an n-type semiconductor with a flat-band potential equal to -0.589 V and a carrier concentration of 6.1020 cm-3. Such a high concentration of carriers is obviously due to the small thickness of the oxide film and its nonstoichiometry, as a result of which the surface is not very depleted in electrons, since titanium metal acts as their donor. [ABSTRACT FROM AUTHOR]