Browsing by Author "Turalioglu, Kerem"

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Determining the Tribological Behavior of 316L Stainless Steel with Lubricating Micro-Channels Produced by the Selective Laser Melting (SLM) Method
(Emerald Group Publishing Ltd, 2021) Turalioglu, Kerem; Taftali, Merve; Yetim, Fatih
Purpose This study aims to produce lubricating surfaces with micro-channels by the selective laser melting (SLM) method, and to investigate their tribological behavior. Design/methodology/approach In this study, three kinds of samples with different geometries were designed, impregnated with oil and then subjected to flow analysis in a virtual environment using Ansys Fluent software. According to the results of these analyses, the best-lubricated surface geometry sample was identified, and a number of geometries were produced by SLM, which is one of the additive manufacturing methods. Tribological tests were performed using a pin-on-disk tribometer with a stainless steel ball as the contact surface. The structural and morphological features were investigated by a three-dimensional profilometer and scanning electron microscopy. Findings The results obtained showed that the impregnated oil reached the surface of the sample compared to untreated samples, and it was seen that the wear rates were reduced, and that the impregnated oil samples exhibited the highest wear resistance. Originality/value In this study, solid geometries that are difficult to be produced by other methods are produced with additive manufacturing method, and the surfaces have been given lubricating properties.
Improvements in the Static/Dynamic Strength of Porcelain Fused to Metal Dental Crowns with Surface Protrusions Produced by Selective Laser Melting
(Elsevier Sci Ltd, 2021) Taftali, Merve; Turalioglu, Kerem; Yetim, A. Fatih; Uzun, Yakup; Akpinar, Salih; Yildiz, Fatih
Porcelain fused to metal dental crowns (PFMDC) are widely used in dental applications. Although the dental crowns are usually produced by the conventional casting method, additive manufacturing (AM) has recently gained an increased interest in dentistry due to its easy and rapid fabrication. Additive manufacturing is also a very advantageous method in patient-specific dental designs. In addition, through this method, it is possible to obtain products with geometries that cannot be obtained by classical methods. It is important to increase the lifetime of products in dental applications for lower costs and improved patient psychology. By increasing the strength of metal?ceramic interfaces, the total strength of dental crowns can be increased. For that reason, metal crowns with different numbers of protrusions and different locations on their surface edges were designed and produced by the selective laser melting method which is one of the additive manufacturing methods. These crowns were tested under both static and dynamic loading conditions and they mechanical performance was compared with the crowns produced by conventional methods. It was found that the crowns, which had different numbers of protrusions and different locations on the surface edge, showed more resistance under both static and dynamic load conditions. It was found that a metal substructure with dense protrusions that was produced at a thickness of 0.3 mm showed the highest strength under both static and dynamic loads.
Novel Two-Step Synthesis and Characterization of Oxide-Free Vanadium Diselenide Thin Films
(Springer, 2025) Ozerbas, Zeynep Elif; Coskun, Ayca; Turalioglu, Kerem; Caglar, Mehtap Aygun; Turgut, Guven
Vanadium diselenide (VSe2) has attracted a significant attention for spintronic and memory devices, catalytic reactions, and sensors because of its superior magnetic and electrical properties. However, the high oxidation tendency of vanadium (V) makes the synthesis of VSe2 challenging, making it one of the least studied two-dimensional (2D) materials. In the present study, a novel two-step method was developed to synthesize oxide-free VSe2 thin films. In the first step, V metallic film was deposited on SiO2/Si substrates using radio frequency (RF) sputter method. X-ray diffraction (XRD) measurements showed that the V thin film oxidized in the form of VO0.532 crystal structure. After VO0.532 film was thermally selenized in a chemical vapor deposition (CVD) reaction tube, both VxOy and VSe2 structures were observed. The oxidation was successfully suppressed by pre-hydrogenation before thermal selenization. Subsequently, the thermal selenization was carried for varying durations, and different phases of V and Se were obtained depending on the selenization time. It was also found the thickness values of the films were strongly dependent on the selenization time. The electrical measurements were conducted on the VxSey films, and their electrical properties were compared based on selenization time.
Recent Studies of Theoretical Gas Sensing Properties of 2D TMDc Janus Materials
(Elsevier Science Sa, 2025) Kopar, Ahmet Serdar; Coskun, Ayca; Ozerbas, Zeynep Elif; Kucuk, Bengusu Alkim; Turalioglu, Kerem; Coban, Omer; Turgut, Guven
In parallel with rapid development in the industry, the amount of toxic and greenhouse gases released into the atmosphere is increasing daily. Therefore, it is of great importance to detect, capture, and eliminate toxic and greenhouse gases, to leave a cleaner environment to future generations. From the past to the present, many studies have been carried out to successfully realize and improve the processes of detecting, capturing and eliminating toxic and greenhouse gases. Gas sensing technology is crucial for environmental monitoring, industrial safety, and healthcare. As a sensing material, transition metal dichalcogenides (TMDCs) have been promising owing to their electronic and chemical properties. It has been theoretically determined that Janus materials, which have been experimentally synthesized in recent years, have promising gas-sensing behaviors. In the present work, to better understand the gas-sensing properties of Janus TMDC materials, theoretical studies in the literature have been reviewed in detail. It consists of the adsorption behaviors of various gases for different sides of Janus materials, and the effect of defects, surface doping/functionalization, strain, and out-of-plane electrical field on sensing mechanisms of Janus materials. As a result of this review, it can be concluded that TMDC Janus materials with surface modifications, strain, and external electric field are promising in gas detection applications.
Synthesis and Characterization of Wear and Corrosion Resistant Ni-Doped Al2O3 Nanocomposite Ceramic Coatings by Sol-Gel Method
(Elsevier Science SA, 2022) Yetim, Tuba; Turalioglu, Kerem; Taftali, Merve; Tekdir, Hilmi; Kovaci, Halim; Yetim, Ali Fatih
Cp-Ti is frequently used in biomedical applications because of its good corrosion and high biocompatible properties. However, its poor wear resistance limits its use in some applications. Therefore, this study aims to improve its wear and corrosion resistance by producing Ni-doped Al2O3 nanocomposite coatings on Cp-Ti. In order to achieve this goal, undoped Al2O3 and Ni-doped Al(2)O(3 )nanocomposite ceramic coatings were produced on Cp-Ti samples at two different rotational speeds by the spin coating process, which is a sol-gel method. Afterward, their structural and morphological features were examined by XRD, SEM, Raman, and 3D surface profilometer. Reciprocating wear tests and electrochemical investigations were performed to determine their wear and corrosion properties.