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- MakaleAçık Erişim2017Scopus SJRQ3Influence of Duplex Treatment on Structural and Tribological Properties of Commercially Pure Titanium
Çelik, Ilhan
Titanium and its alloys are widely used in many fields, including aerospace and the chemical and biomedical industries. This is due to their mechanical properties, excellent corrosion resistance, and biocompatibility although they do have poor wear resistance. In this study, a duplex layer was successfully formed on the commercially pure titanium surface by duplex treatments (plasma nitriding and physical vapor deposition (PVD)). In the initial treatment, plasma nitriding was performed on the pure titanium samples and in the second treatment, the nitrided samples were coated with CrN by PVD. The friction and wear properties of the duplex-treated samples were investigated for tribological applications. Surface morphology and microstructure of the duplex-treated samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, the tribological properties were investigated using pin-on-disc tribometer. A compound layer composed of ϵ-Ti2N and δ-TiN phases and a diffusion layer formed under the compound layer were obtained on the surface of pure titanium after the nitriding treatments. CrN coated on the nitrided surface provided an increase in the surface hardness and in the wear resistance.
AtıfScopus4WoS4İncele - MakaleYalnız künye2016Scopus SJRQ2Influence of CrN Coating on Electrochemical Behavior of Plasma Nitrided Pure Titanium in Bio-simulated Environment
Çelik, Ilhan
Titanium and its alloys are widely used as materials for bio-medical applications, such as implants. However, ions of the alloy can release to the body region and spread into the blood circulation. In this study, plasma nitriding and CrN coating techniques are used in order to overcome the problem of ion release. The objective of this study was to investigate the effects of plasma nitrided pure titanium on the structural properties and corrosion behaviors before and after CrN coating in Ringer's solution at 37 °C. The structural properties were investigated using Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). A diffusion layer and a compound layer composed of δ-TiN and ε-Ti2N phases were observed on the surface of nitrided pure titanium. Corrosion tests were made for the determination of electrochemical properties with the help of Potentiostat/Galvanostat device. The results show that corrosion behaviors of untreated and treated samples have similar characteristic.
AtıfScopus19WoS15OpenAlex19İncele - MakaleAçık Erişim2016Scopus SJRQ3Investigation of structural and tribological properties of duplex surface treated pure titanium
Çelik, I.; Karakan, M.
Commercial pure titanium (CP-Ti) is used in many engineering fields because of its superior properties such as excellent corrosion resistance, high strength/weight ratio, and biocompatibility. However, it is not available at the desired rate, since the CP-Ti has poor wear resistance. For this reason, many surface treatments have been applied to improve the poor tribological properties of the CP-Ti. In this study, duplex surface treatments, which are the combination of treatments of electroless Ni-B coating and plasma nitriding, were applied on the surfaces of the CP-Ti. Structural properties of the different surfaces of the treated materials were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Microhardness measurements were made for the determination of mechanical properties and the pin-on-disk wear tests were made to determine the tribological properties. It was observed that poor wear resistance of the CP-Ti was improved with duplex surface treatments. The results showed that surface hardness, friction coefficient, and surface roughness of coated samples were better than of uncoated CP-Ti.
AtıfScopus7WoS5OpenAlex6İncele - MakaleYalnız künye2016Scopus SJRQ2Effect of plasma nitriding treatment on structural, tribological and electrochemical properties of commercially pure titanium
Çelik, Ilhan; Karakan, Mehmet
In this study, plasma nitriding treatment was applied to commercially pure titanium (Grade 2). Structural properties, electrochemical and tribological behaviours of the nitrided pure titanium specimens were comparatively investigated. Microstructure and morphology of the plasma nitrided specimens were analysed by X-ray diffraction and scanning electron microscopy. Furthermore, corrosion tests were conducted in Ringer's solution, which represents a human body environment, to determine electrochemical properties. Then, tribological and frictional properties were investigated using pin-on-disc tribometer, and a micro-hardness tester was used to measure the hardness of the coatings. The results showed that plasma nitrided specimens exhibited higher surface hardness than the untreated specimens did. In addition, the plasma nitrided specimens at 700 °C presented significantly better performance than the other plasma nitrided specimens (at 500 °C and 600 °C) under dry wear conditions. Moreover, corrosion test results showed that corrosion behaviours of untreated and nitrided samples had similar characteristic.
AtıfScopus9WoS6OpenAlex11İncele - MakaleYalnız künye2016Scopus SJRQ4Effect of chemical Ni – B coating on the structure and tribological properties of plasma nitrided pure titanium
Çelik, Ýlhan; Karakan, Mehmet
The structure and the wear resistance of commercial-purity titanium subjected to plasma nitriding followed by chemical deposition of a Ni – B coating are studied.
AtıfScopus4WoS4OpenAlex4İncele - MakaleYalnız künye2014Scopus SJRQ1Effect of different surface oxidation treatments on structural, mechanical and tribological properties of ultrafine-grained titanium
Çelik, Ilhan; Alsaran, Akgün; Purcek, Gencaga
Four different surface oxidation treatments, so-called, anodizing oxidation (AO), micro-arc oxidation (MAO), plasma oxidation (PO) and thermal oxidation (TO), were applied to ultrafine-grained (UFG) pure titanium produced by equal-channel angular extrusion/pressing (ECAE/P). Before and after all treatments, mechanical, structural and tribological properties were investigated. The strength of pure titanium increased substantially after ECAE process. TiO2 phases included the anatase and/or the rutile formed on the surface of UFG Ti depending on oxidation treatments. High strength of UFG Ti was deteriorated by TO and PO treatments because of the recrystallization occurred at high-temperature, while applications of MAO and AO did not cause a significant decrease in its strength due to the prevention of recrystallization of UFG Ti. All oxidation treatments brought about a remarkable increase in wear resistance of UFG Ti because of the formation of adhered and hard TiO2 film developed on the surface. It was concluded that the AO and MAO treatments could be applied to the UFG Ti without any deteriorations in bulk mechanical and wear properties to obtain biocompatible pure titanium with high strength and excellent wear resistance.
AtıfScopus51WoS47OpenAlex50İncele