WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 8Citation - Scopus: 8Crystallization and Additional Oxide Interlayers Improve the Tribocorrosion Resistance of Tio2 Nanotubular Surfaces Formed on Ti6al4v(Elsevier, 2023) Çaha, İhsan; Türü, İrem Cemre; Erdoğan, Ece; Pinto, Ana Maria Pires; Cansever, Nurhan; Deepak, Francis Leonard; Toptan, Fatih; Alves, Alexandra C.TiO2-based nanotubular surfaces have promising properties for various industrial applications, such as solar cells, fuel cells, photocatalysis, energy storage, gas sensors, and biomedical applications. However, they have very limited use in real applications, and one of the major limiting factors is the weak adhesion of nanotubular surfaces to the substrate. In this study, nanotubular surfaces are formed on Ti6Al4V alloy by anodic treatment followed by a heat treatment at 500 °C for 3 h under an open atmosphere. Microstructural investigations revealed self-organized nanotubes grown on both ? and ? phases. High-resolution TEM/STEM analysis showed crystallization of the nanotubular layer and formation of additional oxide interlayers resulting in a drastic improvement in tribocorrosion resistance. These findings indicated that a simple heat treatment can significantly alter the properties of nanotubular layers and can widen their usage mainly for load-bearing implant applications in corrosive environments. © 2023 Elsevier B.V.Article Citation - WoS: 3Citation - Scopus: 1Corrosion Resistance and Mechanical Properties of Quenched and Tempered 28mncrb5 Steel in Two Acidic Environments(Carl Hanser Verlag, 2017) Yazıcı, Aysel; Zeybek, M. Sadrettin; Güler, Hüseyin; Pınar, Ahmet Murat; Tücer, RenasMicrostructure, hardness distribution, tensile properties and fracture behavior of the quenched and tempered steel 28MnCrB5 were investigated before and after corrosion tests. The corrosion behavior of the quenched and tempered steel 28MnCrB5 was examined in two different acidic environments, namely a hydrochloric acid solution and fertilizer-containing soil. The specimens were immersed in corrosive environments for 24, 48, 72, 96, 120, 144 and 168 hours, and additionally into fertilizer-containing soil for 240 days. The corrosion losses were determined by measuring the weight changes and the respective corrosion rates were calculated. Ductile fracture was observed in the sample of the quenched and tempered material before and after 168 hours of exposure to the hydrochloric acid solution and fertilizer-containing soil environment. But, in the sample subjected to corrosion in the fertilizer-containing soil environment for 240 days, brittle fracture took place and the fracture topography on the surface exhibited inter-granular cleavage. After 240 days of corrosion test in the fertilizer-containing soil environment, the ductility of the material decreased to a very great extent. The surface of the quenched and tempered 28MnCrB5 samples was covered by corrosion pits, cracks and peelings at the end of 168 h tests in the hydrochloric acid solution environment. At the end of 240 day tests in the fertilizer-containing soil environment, the surface of the samples showed deep peelings and cracks.Article Citation - WoS: 10Citation - Scopus: 10The Influence of Plasma-Based Nitriding and Oxidizing Treatments on the Mechanical and Corrosion Properties of Cocrmo Biomedical Alloy(Springer Verlag, 2018) Noli, Fotini; Pichon, Luc; Öztürk, OrhanPlasma-based nitriding and/or oxidizing treatments were applied to CoCrMo alloy to improve its surface mechanical properties and corrosion resistance for biomedical applications. Three treatments were performed. A set of CoCrMo samples has been subjected to nitriding at moderate temperatures (~ 400 °C). A second set of CoCrMo samples was oxidized at 395 °C in pure O2. The last set of CoCrMo samples was nitrided and subsequently oxidized under the experimental conditions of previous sets (double treatment). The microstructure and morphology of the layers formed on the CoCrMo alloy were investigated by X-ray diffraction, Atomic Force Microscopy, and Scanning Electron Microscopy. In addition, nitrogen and oxygen profiles were determined by Glow Discharge Optical Emission Spectroscopy, Rutherford Backscattering Spectroscopy, Energy-Dispersive X-ray, and Nuclear Reaction Analysis. Significant improvement of the Vickers hardness of the CoCrMo samples after plasma nitriding was observed due to the supersaturated nitrogen solution and the formation of an expanded FCC γN phase and CrN precipitates. In the case of the oxidized samples, Vickers hardness improvement was minimal. The corrosion behavior of the samples was investigated in simulated body fluid (0.9 pct NaCl solution at 37 °C) using electrochemical techniques (potentiodynamic polarization and cyclic voltammetry). The concentration of metal ions released from the CoCrMo surfaces was determined by Instrumental Neutron Activation Analysis. The experimental results clearly indicate that the CoCrMo surface subjected to the double surface treatment consisting in plasma nitriding and plasma oxidizing exhibited lower deterioration and better resistance to corrosion compared to the nitrided, oxidized, and untreated samples. This enhancement is believed to be due to the formation of a thicker and more stable layer.