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In this study, the effect of different laser beam power on the nanoindentation and corrosion properties of Ti-6Al-4V alloys fabricated direct metal laser sintering (DMLS) method was investigated. Ti-6Al-4V samples were fabricated by DMLS method with three 34.72 J/mm3, 64.81 J/mm3 and 83.33 J/mm3 energy densities named as sample 1, sample 2 and sample 3, respectively. The microstructure and crystalline phase of Ti-6Al-4V samples were analyzed by optical microscope, SEM and XRD devices. Microstructural examinations showed that microstructure of Ti-6Al-4V samples consisted of the prior columnar β grains and α/α´ phases. The β phase proportion soared with rising laser beam power. Nanoindentation results illustrated that the order of reduced elastic modulus (Er) values was sample 1 > sample 2 > sample 3. The order of hardness (H) values followed sample 1 > sample 2 > sample 3. The H/ Er ratios were found to be 0.0338, 0.0333, and 0.032 for samples 1, 2, and 3, respectively. The H3/Er2 ratios were estimated to be 0.00734 GPa, 0.00633 GPa, and 0.00513 GPa for samples 1, 2, and 3, respectively. The presence of high values means better anti-wear capacity and good resistance to deformation for samples based on nanoindentaion findings. Moreover, electrochemical measurements depicted that the value of corrosion current density (icor) of the samples ordered as sample 3 > sample 2 > sample 1. The sample 1 exhibited better corrosion resistance than other samples. The findings showed that as the laser power is low, DMLS Ti-6Al-4V samples potentially have better mechanical and corrosion performance due to low β content and high α´ phases in the microstructure.

In this study, titanium dioxide (TiO2) nanostructures were produced on pure titanium in different electrolytes at constant voltage of 20 V for 30 min. The crystallographic structure, surface morphology, and optical properties of the films were investigated by XRD, SEM, and UV-vis spectrum, respectively. The wettability of the samples was determined by contact angle measurement equipment. The photocatalytic properties of the TiO2 films were tested by the degradation of a methylene blue (MB) as the model reaction under UV light irradiation. The results showed that the electrolyte composition can play an important role in the surface morphology of nanostructured TiO2 films and therefore on various properties such as optics, electronics, sensing, and degradation. The SEM images of the samples demonstrated that surface morphology was directly affected by the electrolyte composition. It is known that the surface area is a dominant factor affecting the photocatalytic activity of a porous TiO2 layer prepared by anodic oxidation. The TiO2 film (sample C) anodized in 1 M Na2SO4 containing 5 wt.% NH4F exhibited better photocatalytic performance as compared to the other oxide films. This is because a higher surface area with dense pore structure favors more photocatalytic active areas. The photocatalytic degradation efficiency of MB using sample C was reached to 92.35% and rate constant 5.92 x 10(-3), respectively. Moreover, this sample showed lowest band gap energy that was almost 3.167 eV. We believe that new anodic TiO2 nanoporous structures are highly promising in photocatalytic decomposition of water and pollutants elimination.

This work aimed to comprehensively assess the influence of various surface modifications on the formation of apatite ability for EBM Ti-6Al-4V alloy. Sandblasting (S), acid-etching (E), sandblasting and acid-etching (SE), anodization (NA), micro-arc oxidations in 1M H2SO4solution (SM) and 1M H3PO4solution (PM) methods were applied to modify electron beam melted (EBM) Ti-6Al-4V surface. The α/α’-Ti structures and TiO2phases were detected by XRD. The surface roughness (Ra) values ranged from 0.25 μm and 2.86 μm. The wettability of samples was between around 25° and 104°. The SM sample possessed the lowest contact angle. In vitro tests were employed in the simulated body fluid (SBF) solution for 28 days. The samples with different surface textures demonstrated bioactive behaviors. In vitro test results showed that apatite layers formed on the surfaces. The SM sample exhibited good apatite formation ability when the Ca/P ratios were considered. The apatite formation for the SM sample might derive from high roughness, low contact angle value, the existence of Ti-OH groups, and anatase and rutile phases. The SM can be implemented to boost bioactivity on EBM Ti-6Al-4V alloys.

In this work, Zn-Ni-, Zn-Co-, Ni-Co-, and Zn-Ni-Co-coated alloy films were electrodeposited on titanium substrate. The coated alloy films were annealed in order to form oxides at 800 °C in air for 2 h. The crystalline structures, surface morphologies, and chemical composition of the samples were examined using X-ray diffraction techniques (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX). Photocatalytic performance of samples was performed by means of the degradation of methylene blue (MB) under UV irradiation. The SEM results showed that the different morphologies such as needle-shaped nanowires, grains, and pores were formed on the surface. The results showed that the photocatalytic performance of the samples demonstrated differences according to alloy type. The Zn-Ni alloy coating exhibited better photocatalytic activity. Photocurrent measurements illustrated that Zn-Ni sample possessed the highest suppression of photogenerated charge carrier recombination and lowest charge transfer resistance (Rct) layer. It is expected that this work could provide a promosing way for fabricating Zn-based photocatalyts in environmental redemediation.

In this study, TiO2 powders were produced via sol-gel route at 500 degrees C for 2 h with distinct heating rates. TGA-DTA, XRD, SEM, Raman spectroscopy, XPS, UV-vis spectroscopy and photoluminescence characterization techniques were carried out for TiO2 powders. Photocatalytic efficiency of TiO2 powders on degradation of methylene blue (MB) solution was examined in terms of different heating rates. Thermodynamic and non-isothermal kinetic study of TiO2 powders were estimated. TiO2 powders showed anatase phase based on XRD results. Surface morphology of TiO2 powders did not change with different heating rates. It can be concluded that heating rate played important role on band gap and photocatalytic activity. The band gap of the TiO2 particles decreased from 3.25 to 2.95 with increasing heating rate. The photocatalytic activity results exhibit that T1 powders have the highest photocatalytic performances. The kinetic constant and photocatalytic degradation rate were 0.00678 min(-1) and 83.48%, respectively. This could be attributed to high crystalline structure and low bulk vacancies or defects. Furthermore, TiO2 powders showed good stability. This study exhibited a new way to enhance the photocatalytic performances of pure TiO2 powders.

In this study, micro- and nanosurface structures were fabricated by sandblasting (S), acid-etching (E), anodic oxidation (A), sandblasting/acid-etching (SE), sandblasting/anodization (SA) and sandblasting/acid-etching/anodization (SEA) processes on Ti6Al4V alloy in order to investigate apatite formation ability. The phase, morphology, topography, roughness and wettability properties of surfaces were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), surface profilometer and contact angle techniques. In vitro tests were performed in simulated body fluid (SBF) for 21 days. The results showed that the surface topography, roughness and wettability changed the Ca and P ion ratio. The SEA sample had high surface topography and the lowest contact angle value. The value of Ca/P ratio was 1.81 for SEA sample. The SEA sample showed the highest Ca/P ratio value which was close to theoretical value. Ca and P ion ratio value because of bioactive phases on the surfaces, high surface roughness and lower contact angle values as compared to other samples. The proposed methodology improves the apatite formation ability of Ti6Al4V alloys. Sandblasted/acid-etched/anodized surfaces can be an alternative to conventional sandblasted/acid-etched implant surfaces.

Structural colorization with photonic crystal structures draws high attention with fadeless bright color, combined with low toxic and eco-friendly features. It has been suggested for the first that the Titanium (Ti) surface coloration, which was not explained properly until now, is due to the photonic crystal structure. A dyeing process to be applied on the Ti/TiO2 will dampen their photocatalytic properties. However, the thin film grown on the Ti surface by the suggested anodizing process allows the formation of harmless structural colors and keeps photocatalytic performance. Ti substrates were anodized in HF and H3PO4 based solutions at voltage values between 10 V and 80 V. Structural, morphological, optical, and photocatalytic properties of the TiO2 thin films were characterized in order to determine anodization solution type and voltage. Similar to some butterfly wings, it is mentioned that the repeated lamellar and porous structures observed on the surfaces cause photonic crystal interactions with dielectric variations. It can be said that the anodization voltage value but not the anodization solution type can control the obtained structural violet, blue, yellow, orange, and red colors. Samples anodized at lower voltages exhibited better photocatalytic performance due to higher photon harvesting. Thus, we have proved in our study that both the photocatalytic property is not extinguished and that structural colors can be obtained.

In this study, Zinc oxide (ZnO) nanowires (NWs) were successfully produced on Zn plates through electrochemical anodization in potassium bicarbonate aqueous electrolytes with different production parameters in two groups as applied voltage and anodization time. Subsequently, the ZnO NWs were annealed at 300 ℃ for 1 h in air atmosphere to increase crystallinity and remove organic residues. Structural and morphological properties were determined through X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The effect of anodization parameters on the structure of ZnO NWs and thus their photocatalytic activities were evaluated in detail by UV spectrophotometer. The results pointed out that, the most effective nanostructure on the photocatalytic degradation of methylene blue was obtained at the sample anodized under 30 V for 30 min at room temperature with 90.6% degradation efficiency among the samples. This result shows that the NW structured ZnO materials are promising to be used as effective photocatalysts in the removal of organic pollutants by solar energy and their conversion to green compounds.

Titanium thin films were deposited on glass and indium tin oxide (ITO) coated glass substrates by radio-frequency (RF) magnetron sputtering under varying sputtering parameters as: power, pressure, substrate temperature and target-substrate distance. The crystalline structure, crystallite size and texture coefficients of the films were evaluated in detail. As the evaluation points out, 100 W, 1.33 Pa ambient temperature and 70 mm were determined as the optimum sputtering parameters for intended crystalline structures. Subsequently, electrochemical anodization experiments were performed via varied electrolytes and under various anodization parameters (voltage, time and electrolyte type) in a two-electrode electrochemical cell using the films obtained through the optimized sputtering parameters. The anodized samples were annealed at 450 °C for 1 h in air in order to obtain anatase transformation and the desired crystalline structure. The surface morphologies and the crystalline structures of the anodized films were evaluated through x-ray diffractometer (XRD) and scanning electron microscope (SEM), respectively. Finally, the anodization parameters for the formation of TiO2 nanotube arrays were determined as: 35 V and 35 min. in an electrolyte composed of 0.3 wt.-% NH4F – 2 wt.-% water – ethylene glycol.

In this study, silver (Ag)-doped titanium dioxide/reduced graphene oxide (Ag@TiO2/rGO, TGA) hybrid photocatalysts were synthesized for enhanced photocatalytic properties. TGA hybrid photocatalysts were synthesized through a facile sol-gel method. Synthesis of graphene oxide (GO) nanoparticles were obtained by Hummer's method followed by chemical reduction to obtain rGO nanoparticles. Ag doping was carried out at the sol stage of the sol-gel synthesis. Increasing amounts of Ag nanoparticles from 0.5 wt.% to 4 wt.% were added to increase the degradation effect of methylene blue (MB) under UV light irradiation. X-ray diffractometry (XRD), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), UV-vis spectrophotometry, photoluminescence spectroscopy (PL), and diffuse reflectance spectroscopy (DRS) were used to investigate the crystal structure, topography, morphology, chemical and optical properties of the samples, respectively. Samples were calcined in order to obtain the anatase phase at 500 degrees C with a heating rate of 10 degrees C/min for 2 h in air atmosphere. The effect of Ag content on the photocatalytic properties of TiO2 based nanocomposite material was observed by keeping the weight ratio of rGO constant at 4 wt.%. Ag addition into the TiO2/rGO matrix exposed an excellent photocatalytic activity under UV light irradiation than that of undoped TiO2/rGO photocatalyst. The absorbance value of MB was degraded from 0.683 to 0.011 at 664 nm by TGA1 sample for 240 min. This demonstrated that the TGA1 hybrid photocatalyst containing 1 wt.% of Ag exhibited the highest degradation efficiency of 98.4%. This paper indicates the potential photocatalytic application of Ag-doped TiO2/rGO photocatalysts on the removal of dissolved organic pollutants in water.

İleri oksidasyon teknolojilerinden biri olan fotokatalitik bozunma, organik kirleticilerin temizlenmesinde ve su arıtımında ümit verici yöntemlerden biri olmaya başlamıştır. Fotokatalistler arasında en dikkat çekeni ise, yüksek fotoaktiviteye sahip, kararlı ve düşük maliyetli olan titanyum dioksit (TiO2) yarı iletken malzemesidir. Bu çalışmada TiO2 kaplamalar, fosforik asit (H3PO4) içerikli elektrolit içerisinde saf titanyumun anodik spark oksitleme metodu ile anotlanması sonucu üretilmiştir. Farklı elektrolit konsantrasyonlarının (0.25-2 M H3PO4) altık yüzeyinde oluşan TiO2’nin mikroyapısına, yüzey morfolojisine ve fotokatalitik performansına olan etkileri incelenmiştir. TiO2 kaplamaların kristalin fazları X ışını kırınım cihazı (XRD) ile belirlenmiştir. Yüzeylerin mikroyapısı, taramalı elektron mikroskobu (SEM) ile analiz edilmiştir. Örneklerin fotokatalitik aktivite testleri, farklı zaman aralıklarında UV ışık altında metilen mavisi çözeltisinin bozundurma çalışmaları ile saptanmıştır. En yüksek fotokatalitik aktivite 1 M elektrolit konsantrasyonunda üretilen TiO2 kaplamasında elde edilmiştir. Deneysel çalışma sonuçları, hem morfolojideki hem de kristal yapıdaki değişikliklerin TiO2 kaplamaların fotoaktivitesi üzerinde güçlü bir etkiye sahip olduğunu göstermiştir.&nbsp, Photocatalytic degradation, one of the advanced oxidation technologies, has begun to be one of the promising methods for cleaning organic contaminants and for water treatment. The most notable among photocatalysts is titanium dioxide (TiO2) semiconducting material with high photoactivity, stable and low cost. In this study, TiO2 coatings were produced by anodic spark oxidation method on pure titanium in H3PO4 containing electrolyte. The effects of different electrolyte concentrations (0.25-2 M H3PO4) on the microstructure, surface morphology and photocatalytic performance of TiO2 coatings have been investigated. The crystalline phases of the TiO2 coatings obtained were determined by XRD. The microstructure of the surfaces was analyzed by SEM. The photocatalytic activity tests of the samples were evaluated by the degradation of aqueous methylene blue solutions under UV light at different time intervals. The highest photocatalytic activity was obtained in the TiO2 coating produced in a 1 M electrolyte concentration. The results indicated that changes in both the morphology and crystalline structure have a strong influence on the photoactivity of the TiO2 coatings.&nbsp

In this work, iodine (1) doped hollow and mesoporous Fe2O3 photocatalyst particles were fabricated for the first time through sol-gel method. Phase structure, surface morphology, particle size, specific surface area and optical band gap of the synthesized Fe2O3 photocatalysts were analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscopy (XPS), BET surface analysis, particle size analyzer and UV-vis diffuse reflectance spectrum (UV-vis DRS), respectively. Also, electrochemical properties and photoluminescence spectra of Fe2O3 particles were measured. The results illustrated that high crystalline, hollow and mesoporous Fe2O3 particles were formed. The optical band gap values of the Fe203 photocatalysts changed between 2.104 and 1.93 eV. Photocatalytic efficiency of Fe2O3 photocatalysts were assessed via MB solution. The photocatalytic activity results exhibited that I doping enhanced the photocatalytic efficiency. 1% mole iodine doped (I-2) Fe2O3 photocatalyst had 97.723% photo degradation rate and 8.638 x 10(-2) min(-1) kinetic constant which showed the highest photocatalytic activity within 45 min. Moreover, stability and reusability experiments of Fe2O3 photocatalysts were carried out. The Fe2O3 photocatalysts showed outstanding stability after four sequence tests. As a result, I doped Fe2O3 is a good candidate for photocatalysts. (C) 2017 Elsevier B.V. All rights reserved.

© 2021 Elsevier B.V.In this study, Ti-6Al-4V alloys were additively manufactured (AM) with different laser powers. The goal was to investigate the effect of different surface modifications on apatite formation ability. Four types of surface modifications, namely, sandblasting (S), acid etching (E), anodic oxidation (AO) and anodic spark oxidation (ASO), were achieved on the Ti-6Al-4V samples. The microstructure, phase, morphology, roughness and wettability properties were examined by optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), surface profilometer and contact angle techniques. The bioactivity analysis was performed in simulated body fluid (SBF) for 2 weeks. The results indicated that the microstructure, surface topography, roughness and wettability influenced the apatite formation were affected by the production laser power. Generally, the samples 3 showed higher Ca and P ion ratio value because of percentage of β phase amount, the presence of bioactive phases on the surfaces. The E3 sample resulted in the best apatite formation theoretically. The etching procedure of AM Ti-6Al-4V in the acidic solution can be applied to improve the apatite formation ability of Ti-6Al-4V alloys.

In this paper, zinc oxide (ZnO) nanowires were synthesized by thermal oxidation method of zinc scrap at various temperatures ranging between 400 degrees C and 900 degrees C under air atmosphere. The influence of different temperature on the phase structures, surface morphologies and photoelectrochemical (PEC) properties of ZnO nanowires were investigated. The characterizations were carried out via X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The results showed that annealing temperature played a significant role on surface morphology and phase structure. The band gap energy of the ZnO nanowires changed between 3.12 and 3.194 eV. The photoelectrochemical (PEC) study of the ZnO nanowires was investigated in 0.1 M Na2SO4 aqueous solution. The PEC findings represented that the ZnO nanowire annealed at 600 degrees C had 252.2 mu A/cm(2) net photocurrent density which was the best efficiency and at least 10 times higher than that of the lowest one at 1.25 V (vs. V-RHE). Mott-Schottky analysis showed that the ZnO nanowires behaved as n-type semiconductor. ZnO nanowire annealed at 600 degrees C had the highest carrier density value (N-d = 9.03 x 10(23)). Moreover, the charge transfer behavior of the ZnO nanowires was determined by means of electrochemical impedance spectroscopy (EIS) measurements. As a result, this work recommends that the ZnO nanowires could be good candidate on PEC applications. Also, thermal oxidation method is an efficient method for fabrication of ZnO nanowires. (C) 2018 Elsevier B.V. All rights reserved.

Bu calismada, Ni-Co alasimli kaplamalar elektrolitik yontemle celik malzeme yuzeyine sulfat banyosundan bir guc kaynagi yardimiyla hazirlanmistir. Elektrolit icinde Co miktarindaki degisimin kaplamanin kompozisyon, faz yapisi ve morfoloji uzerine etkileri incelenmistir. Elde edilen kaplamalar; X‑isini kirinim cihazi (XRD) ve taramali elektron mikroskobu (SEM) ile karakterize edilmislerdir. Sonuclara gore, elektrolit icindeki farkli Co konsantrasyonu Ni-Co alasimli kaplama tabakasinin ozelliklerine etki etmektedir. Elektrolitteki Co oraninin artisi ile birlikte alasimli kaplama tabakasinda depozitlenen Co oraninda ciddi bir artis soz konusudur. Ni-Co alasimli kaplama tabakasinda YMK+HSP kristal yapisi artan Co miktari ile HSP yapiya donusmektedir. Ayni zamanda alasimli kaplama tabakasindaki Co oranindaki artis ile birlikte yuzey morfolojisinde degisim gozlemlenmistir ve daha granuler bir yapi olusmustur.

In the present study, cuprous oxide (Cu2O)and cupric oxide (CuO) structures were prepared by thermal oxidation of electroplated copper (Cu) coatings on titanium substrates. The influence of different annealing temperatures from 200 to 600 degrees C on the morphology, crystal structure and the photocatalytic activity of the Cu2O and CuO structures were studied in detail. The photocatalysts were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Photocatalytic activities of the samples were examined by the degradation of methylene blue (MB) under UV light irradiation. The spectroscopic analysis was investigated by UV vis spectrophotometer. The results showed that the microstructure and surface morphology of the samples changed considerably at different annealing temperatures. The sample annealed at 500 degrees C exhibited the highest photocatalytic activity. The results indicated that need-like surface morphology and phase structure play an important role in enhancement the photocatalytic performance of Cu2O/CuO structures. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Bulk and thin film forms of titanium dioxide (TiO2) have been studied many times due to its very promising optical properties. In this study, low-cost flame spray pyrolysis (FSP) synthesis of Nd3+/Er3+ doped TiO2 nanoparticles has been reported for the first time. The produced particles were post-annealed after FSP process at 550 degrees C in order to obtain crystalline structure. The phase and elemental analysis of the produced materials were performed by X-Ray Diffraction (XRD) and X-Ray Photoelectron Spectroscopy (XPS), respectively. The surface morphology, accurate size and specific surface area of the primary particles were identified using scanning electron microscopy (SEM) and particle size analyser. Luminescent properties of the produced nanoparticles were investigated by steady state and time resolved fluorescence spectra. Doping of TiO2 nanoparticles with the rare earths of Nd3+ and Er3+ resulted in visible and near-infrared light emission when excited at 364 nm. The utilized nano particles yielded bi-and tri-exponential decay curves. Additionally, they exhibited typical upconversion luminescence when radiated by 810 nm. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

In this study, we present results of comparative studies on the microstructure and mechanical properties of nanostructured and microstructured titanium dioxide (TiO2) films formed on titanium substrates by electrochemical anodization at different electrolytes. Nanostructured TiO2 film was prepared in 1% HF solution for 30 min. Microstructured TiO2 films were anodized in two different electrolytes (1 M H2SO4 and 1.4 M H3PO4) for 10 min. The phase structures, surface morphologies and surface topographies of the samples were analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscopy (AFM), respectively. The surface hardness and elastic modulus of the TiO2 films were studied using nanoindentation technique. The results showed that the electrolyte type and applied voltage have a strong influence on the morphology and crystalline structure of the TiO2 films. It was found that hardness and elastic modulus of the nanostructured TiO2 film were much lower than the microstructured TiO2 films. (C) 2016 Elsevier B.V. All rights reserved.

In this work, ZnO particles were fabricated by sol-gel method at different heating rate at 500 degrees C for 2 h. The ZnO powders were analysed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and photoluminescence, respectively. The effect of heating rate on photocatalytic activities of ZnO particles was evaluated by degradation of methylene blue (MB). The non-isothermal kinetics and thermodynamic properties were also estimated. The XRD results showed that ZnO had hexagonal wurtzite structure. The different heating rate didn't influence the surface morphology of ZnO powders. It was observed that the heating rate had a profound effect on reduction of band gap and photocatalytic performances. The band gap of the ZnO particles varied from 3.10 to 3.17. The ZnO sample prepared at 1 degrees C/min exhibited the highest photocatalytic activity. Its relative photocatalytic degradation rate and kinetic constant were 92.7% and 1.069x10(-2) min(-1), respectively. The results might be ascribed to low bulk vacancies, high surface oxygen vacancies and narrow band gap energy. Also, ZnO photocatalysts showed good stability after four sequence tests. This study provides a new strategy to improve the photocatalytic performances of ZnO photocatalyst for the degradation of organic contaminant.

In this study, undoped and Zn-doped SnO2 nanoparticles in different concentrations were synthesized by flame spray pyrolysis (FSP) technique. The produced particles were post-annealed after FSP process at 600 °C in order to obtain a crystalline structure. The structural analysis of the produced powders was performed by X-Ray Diffraction (XRD) methods. The surface morphology of the nanoparticles was identified using scanning electron microscopy (SEM). In addition, photocatalytic degradation of aqueous methylene blue (MB) solutions were evaluated using undoped and Zn-doped SnO2 nanoparticles under UV light illumination. Photocatalytic degradation of the MB solutions followed the pseudo-first-order-kinetics and the effect of the Zn doping amount on the photocatalytic reaction was investigated. © 2018, Turkish Chemical Society. All rights reserved.

Porous titanium dioxide (TiO2) coatings were prepared on the pure titanium substrate by anodic spark oxidation (ASO) method in electrolytes containing various concentrations of sulfuric acid. The crystal phase, surface morphology, chemical composition, and optical property of the TiO2 films were analyzed by using XRD, SEM, XPS, and UV-vis spectroscopy. The photocatalytic activity is evaluated by the decomposition of methylene blue (MB) aqueous solution under UV light irradiation. It is found that the electrolyte concentration plays an important role in the properties and characteristics of the TiO2 coatings. The results show that TiO2 films consist of primarily the rutile phase with altering fraction depending on the electrolyte concentration without any heat treatment. The results demonstrated that there were formed too many sub-micron and nanopores of TiO2 neighboring to the micropores. TiO2 layer anodized in 0.75 M H2SO4 exhibited much higher photocatalytic activity than the other films. The results imply that anatase-rutile mixed TiO2 coatings can be successfully used for the photocatalytic degradation of organic pollutants.

In this study, nanostructured anatase titanium dioxide (TiO2) films were fabricated by electrochemical anodization of titanium first, and then annealed at 500 degrees C for 2 h. Effect of electrolyte concentration, anodization time and electrolyte temperature on the surface morphology of the resulting TiO2 thin films were investigated. The phase structures, surface morphology and chemical composition were analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity tests of the samples were evaluated by the degradation of aqueous methylene blue (MB) solutions under UV light illumination for different periods of time. The results showed that the structure of nanostructured TiO2 films depended strongly on the anodization parameters. It was found that there were micro-scale pores (

The aim of this study was to evaluate the effect of electrolyte concentration on the surface morphology, surface topography, wettability and surface roughness of nanoporous titanium dioxide (TiO 2 ) layers. Titanium (Ti) samples were treated by sandblasting and acid-etching processes. TiO 2 layers were formed on sandblasted/acid-etched titanium in electrolytes containing different HF concentration (% 0.25-2). The samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The surface roughness and the wettability of the samples were measured using proilometry and a contact angle measurement system. The samples, which were anodized after sandblasting/acid-etching treatment had amorphous structure and peaks from the substrate were observed. The results showed that with increasing HF concentration, the surface morphology of the samples were significantly changed. All the treated samples exhibited hydrophilic properties.

In this study, micro-nanoporous TiO2 films were prepared by electrochemical anodization of titanium (Gr-2) in an aqueous solution containing 0.5 wt. % HF solution at a constant potential of 30 V and then annealed in ambient air at 500, 600, 700 and 800 °C for 2 h to obtain crystalline structures. The crystalline phase and surface morphology of the samples were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The photocatalytic performances of the samples were evaluated by the photocatalytic degradation of aqueous methylene blue (MB) solutions under UV light illumination for different periods. XRD results indicated that at annealing temperatures higher than 600°C, anatase started to transform into rutile. Increasing annealing temperatures resulted in reduced micro-nanopores diameter and increased wall thickness. At 800°C, the structure completely disappeared. The results demonstrated that changes in both the crystalline structure and surface morphology have a strong influence on the photoactivity of the nanostructured TiO2 films. © 2018, Turkish Chemical Society. All rights reserved.

In this study, the mechanical disc milling was applied to the production of Ti6Al4V powders from the recycling titanium alloy machining scraps. The present study covers the effects of the milling speed and milling time on the characteristics of recycled powders such as particle size, morphology, crystal phases, and oxygen content. The scraps and produced powders were sequentially characterized by XRD, SEM, particle size and elemental oxygen analyses. The results indicated that the milling parameters had a significant effect on the particle size and morphologies of Ti6Al4V powders. The particle size of flaky powders decreased when the milling speed increased from 800 to 1400 rpm for a milling time of 4 min., and the milling time increased from 4 to 24 min. for a milling speed of 1200 rpm. The results showed that the average mean particle sizes (d(50)) are approximately 330 and 211 mm after milling for 4 min at 1400 rpm and for 24 min at 1200 rpm, respectively. Based on the XRD results, a significant change in the phase content was not recorded. Overall, our study demonstrated that the applied milling process is quite effective to produce micron-sized powders from the Ti6Al4V scraps in a short time. (C) 2017 Elsevier B.V. All rights reserved.

Zinc oxide (ZnO) is widely used in different areas thanks to its unique photocatalytic, optic and electrical properties. Sn doped ZnO nanoparticles were synthesized through flame spray pyrolysis (FSP) technique. The Sn dopant concentrations were 1, 3, 5, 7 and 9 at. % in produced ZnO nanoparticles. The structural analysis of the produced powders was performed by X-Ray Diffraction (XRD) methods. The surface morphology and particle size distribution of the nanoparticles were identified using scanning electron microscopy (SEM), and dynamic light scattering (DLS) techniques. In addition to this, produced photocatalysts were evaluated for degradation of aqueous methylene blue (MB) solutions under UV light irradiation. Sn-doped nanoparticles have superior photocatalytic activity compared to un-doped ZnO. © 2018, Turkish Chemical Society. All rights reserved.

In this work, zinc oxide (ZnO) nanostructures were successfully synthesized by thermal oxidation of zinc (Zn) coated steel substrates. Zn coatings were electrodeposited on the mild carbon steel sheet in the sulfate bath by DC current. The zinc coated samples were oxidized in air at distinct annealing temperatures between 400 degrees C and 800 degrees C. The phase structure and surface morphology of the ZnO films were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activity of these ZnO layers was examined by means of decomposition of methylene blue (MB) aqueous solutions under DV lamp irradiation for various duration. The findings illustrated that annealing temperatures had a big effect on the morphology and structure of the ZnO layers. The annealed layers showed significantly enhanced photoactivity activity than the pure Zn layer under UV-irradiation. The sample with ZnO nanostructures oxidized at 800 degrees C exhibited a better photocatalytic degradation of MB than the other samples. This paper can provide an important contribution to the development of efficient photocatalysts for the solution of the environmental pollution problems.

In this work, iodine (I) doped hollow and mesoporous Fe

6th Congress and Exhibition on International Advances in Applied Physics and Materials Science (APMAS) -- JUN 01-03, 2016 -- Istanbul, TURKEY, WOS: 000405202000003, The objective of the innovative approaches of the scintillation materials to be used in the digital portal imaging systems in the radiotherapy applications is to research the GOS material production that has been activated with the rare earth elements (RE), to produce the scintillation detectors that have a rapid imaging process with a lesser radiation and higher image quality from these materials and to apply the radiographic imaging systems. The GOS: Tb3+ showed high emission peak and high x-ray absorption properties which have been determined for application to mammography and dental radiography. In this study, Gd2O2SO4: Tb3+ phosphors were fabricated by the sol-gel method that is a unique technique and not previously applied. Besides, the structural characterization of GOS: Tb3+ has been investigated. The strongest emission peak located at 549 nm under 312 nm UV light excitation was appeared on the GOS: Tb3+ phosphor particles. The characterization processing optimized by using FTIR, DTA-TG, XRD, XPS, SEM and the luminescence spectroscopy.

6th International Congress and Exhibition on Advances in Applied Physics and Materials Science (APMAS) -- JUN 01-03, 2016 -- Istanbul, TURKEY, WOS: 000396118600031, Scintillation materials are widely used in digital X-ray imaging applications, radiotherapy applications coupled with suitable photoreceptors. Gd2O2SO4 (GOS) scintillator doped with trivalent praseodymium (Pr3+) presented high X-ray absorption properties and good spectral compatibility which were utilized extensively for imaging system of X-ray microscopy, soft X-ray phosphor screen for water window. In this study, GOS:0.01Pr(3+) scintillation material was synthesized by unique sol-gel process which was not previously applied and its characterization properties were investigated. Structure and luminescence properties of GOS:Pr3+ were optimized by utilizing X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and luminescence spectroscopy.

6th Congress and Exhibition on International Advances in Applied Physics and Materials Science (APMAS) -- JUN 01-03, 2016 -- Istanbul, TURKEY, WOS: 000405202000004, Radiographic imaging which transforms y or x rays into visible light is one of the most important developments in the field of digital imaging systems in recent years. Materials consisting of rare earth elements have strong scintillation properties in digital radiology. Gd2O2SO4 is studied due to having effective magnetic properties and excellent luminescence spectra. Additionally, Gd2O2SO4: Eu3+ has thermal stability and ideal red light emission performance with peak emission at around 618 nm when activated under X-ray or ultraviolet light. In this study, Gd2O2SO4: Eu3+ nanoparticles were synthesized by sol-gel method and were calcined at 950 degrees C in argon gas atmosphere. In the analysis of the produced nanoparticles XRD, SEM, XPS and optical luminescence devices were used to evaluate the results.

In the present work, nanostructured TiO2 films were prepared by electrochemical anodization process of titanium in fluoride-containing electrolytes using an innovative approach. After anodization, the TiO2 films were annealed at 480 degrees C for 2 h in air in order to acquire anatase phase transformation and increase its crystallinity. The effects of anodization voltage, electrolyte concentration and anodization time on the formation of TiO2 films and the photocatalytic degradation of methylene blue (MB) were discussed in details. The phase structure and surface morphology of the samples characterized by means of X-ray diffraction and scanning electron microscope. The as-prepared nanostructured TiO2 film anodized in 0.5% HF electrolyte at 15 V for 240 min showed excellent photocatalytic degradation of MB and is promising for environmental purification.

In this study, undoped and silver (Ag) doped titanium dioxide (TiO2) films were successfully synthesized by sol-gel spin coating technique on the Si substrates. Photocatalytic activities of the TiO2 films with different Ag content were investigated for the degradation of methylene blue (MB) under UV light irradiation. The crystal phase structure, surface morphology, chemical and optical properties of Ag-doped TiO2 films were characterized using an X-ray diffractometer (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV-vis spectrophotometer, and FTIR spectrophotometer. The results showed that the Ag-doped TiO2 films calcined at 500 degrees C had the crystalline anatase phases and the surface morphologies with some cracks. Ag substitution into TiO2 matrix enhanced the photocatalytic activity of TiO2 films under UV light irradiation as compared to the undoped TiO2 film. Furthermore, the results indicated that the 0.7% Ag doped TiO2 film exhibited a superior photocatalytic activity than that of undoped and other Ag-doped TiO2 films. This study demonstrated the potential of an application of Ag doped films to efficiently treat dissolved organic contaminants in water. (C) 2016 Elsevier B.V. All rights reserved.

In this paper, we present results of comparative studies on the photocatalytic activity of microporous and nanoporous titanium dioxide (TiO2) layers formed on titanium substrates by electrochemical anodization at different voltages. Two sample groups each including four samples was prepared for microporous and nanoporous TiO2 layer formation. Microporous TiO2 layers were prepared in 1 M H2SO4 solution in 10 min. Nanoporous TiO2 layers were formed in %1 HF solution in 30 min and then annealed at 480 degrees C in ambient air. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The photocatalytic activity of the samples was determined by assessing the decomposition rate of methylene blue (MB) solutions under UV light for different periods of time. By using the data obtained from the UV-Visible spectrophotometer, photocatalytic decomposition kinetics was also determined. The results indicated that nanoporous TiO2 layers formed by applying 20 V showed optimal photocatalytic performance, whereas the sample anodized at 250 V exhibited the highest photocatalytic activity within its own sample group, nearly matching the photocatalytic activity of the highest performing sample. (C) 2015 Elsevier B.V. All rights reserved.

Nanoporous titanium oxide (TiO2) layers were fabricated on commercially pure titanium (Cp-Ti) substrates by the anodic oxidation method under a potentiostatic regime. Anodic oxidation was performed in an aqueous solution containing 1 wt% hydrofluoric acid at room temperature for 30 min. Subsequently one of the anodized samples was annealed at 480 degrees C for 2 h in air in order to obtain anatase transformation and increased crystallinity. The average pore diameter of both anodized and anodized+annealed samples were found to be nearly 52 nm and 66 nm, whilst the average inter-pore distances were approximately 65 rim and 76 nm, respectively. Characterization of nanoporous TiO2 layers was carried out through X-ray diffractometer (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV visible spectroscopy. Effects of heat treatment on properties such as crystallinity, morphology and photocatalytic activity were investigated in details. Finally photocatalytic degradation ratios and changes in degradation kinetics under the presence of both anodized and anodized+annealed catalysts were calculated. Depending on the obtained results, the annealed film with anatase structure demonstrated highly efficient photacatalytic performance. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Nanoporous titanium dioxide (TiO2) layers were successfully formed by an electrochemical anodisation method on microroughened titanium (Ti) surfaces in fluoride containing aqueous electrolyte. Microroughened Ti surfaces were produced by sandblasting with Al2O3 particles of 50 μm in diameter and acid-etching in a blend of HCl/H2SO4 solution. The surface morphology, topography and chemical composition of the specimens were analysed by scanning electron microscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The surface roughness and the wettability of treated Ti surfaces were measured using profilometry and a contact angle measurement system, respectively. With anodising of sandblasted-/acid etched surfaces, micrometre- and nanometre-scale textures on titanium specimens were created. Results showed that these developed nanoporous-microroughened surfaces exhibited lower contact angle values than the other treated Ti surfaces. The sandblasted/acid-etched/anodised Ti specimen had a surface morphology with distinctively formed hills and valleys and higher surface roughness than the other anodised specimens. This study indicated that nanoporous TiO2 structures fabricated on microroughened Ti can be an effective way to modify the titanium surfaces for the future development of implant applications., BAP (Department of Scientific Research Projects) 2011.KB.FEN.029; EMUM (Center for Fabrication and Application of Electronic Materials) in Dokuz Eylul University

Ternary zinc–nickel–cobalt alloys were electrodeposited on steel substrates from sulfate bath by direct current. Microstructural and mechanical properties of Zn–Ni–Co ternary alloy coatings were investigated and contrasted with the characteristics of Zn–Ni and Zn–Co alloy coatings. It was found that the obtained Zn–Ni–Co alloy exhibited more preferred surface morphology and mechanical properties as compared to the other alloy coatings electroplated at the same conditions. X-ray diffraction studies showed that the deposits of Zn–Ni–Co alloy coatings consisted of Zn, ZnNi3, and ZnCo13 phases. The structure, surface morphology, and surface topography of the deposited alloys were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray microanalysis (EDS), and atomic force microscopy (AFM). In addition, hardness, elasticity modulus, and adhesion strength of coated alloys were measured with dynamic ultra-microhardness (DUH) and Scratch tester.