Sürdürülebilir Kalkınma Amaçları

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• MakaleYalnız künye2023/r/gumushane/12756
  Enhanced wear resistance and surface properties of oxide film coating on biocompatible Ti45Nb alloy by anodization method

  Şenaslan, Fatih; Taşdemir, Muharrem; Çelik, Ayhan; Bozkurt, Yusuf Burak

  β-Titanium alloys have become increasingly popular as biomaterials because of their low modulus of elasticity and superior corrosion properties in recent years. β-titanium alloy containing niobium is also a biocompatible and non-toxic material. Among β-Ti alloys, Ti45Nb is one of the most remarkable alloys for its superior properties as a biomaterial. This alloy has superior properties due to low elasticity modulus and non-toxic elements, but its surface properties are inadequate for biomaterial applications. Therefore, various surface treatments are applied to improve the surface properties of these alloys. In this study, an oxide film layer was formed on the Ti45Nb surface under different potential conditions by the anodizing method. The effects of these factors on friction, wear, and contact angle measurements were investigated. The structural properties of the oxide film coated samples were analyzed with XRD and their surfaces and cross-sectional images were observed by SEM. Also, the surface roughness and nanoindentation tests were performed. In this regard, it was determined that oxide film thickness, surface roughness and hardness increased with the increase of anodization potential. The contact angle of the samples decreased with the increase in the anodization potential and the surface tension of the materials increased. The highest nanohardness of about 4.19 GPa was obtained from 150 TA samples. The elasticity modulus of the untreated sample was about 63 GPa, while the anodized samples ranged from an average of 31 to 83 GPa. The wear results revealed that the anodization process improved the wear resistance of the Ti45Nb alloy. As a result, the sample anodized at 200 V for 30 min exhibited optimum surface roughness, morphology and high wear resistance.

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• MakaleYalnız künye2014/r/gumushane/13288
  Effect 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.

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• BildiriYalnız künye2011/r/gumushane/10448
  Hydroxyapatite production on ultrafine-grained pure titanium by micro-arc oxidation and hydrothermal treatment

  Alsaran, A.; Purcek, G.; Hacisalihoglu, I.; Vangolu, Y.; Bayrak, O.; Karaman, I.; Celik, A.

  In this study, pure-Ti (Grade-2) was severely plastically deformed by equal-channel angular extrusion (ECAE) to improve its strength, and then subjected to micro arc oxidation (MAO) and hydrothermal treatment (HT) to achieve improved surface behavior with hydroxyapatite (HA)-containing titania (TiO(2)) coating. Microstructure, tensile properties and wear behavior of UFG Ti were investigated systematically before and after surface modification. ECAE considerably enhanced the strength of coarse-grained (CG) Ti by forming an ultra-fine grained (UFG) microstructure with high dislocation density. The application of MAO with or without HT did not cause remarkable decrease in strength and ductility of CG and UFG Ti, but resulted in a considerable increase in its wear resistance and osseointegration due to the formation of hard and adhered HA-containing TiO2 coating on the surface. It can be concluded that the use of ECAE plus MAO/HA coating provides a simple and effective procedure to obtain pure Ti with high strength and high wear resistance. The improved bulk and surface properties can make this biocompatible material a good potential candidate for biomedical applications instead of alloys including toxic elements. (C) 2011 Elsevier B.V. All rights reserved.

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