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- MakaleAçık Erişim2023High-cycle fatigue and tensile strength of AZ91 Mg alloy with MAO-epoxy duplex coating
Karabudak, Filiz
In this study, an epoxy layer was formed by the immersion process, on the oxide layer grown by the micro-arc oxidation (MAO) treatment of the AZ91 magnesium alloy, using the thin film sealing technology, and its effect on fatigue and tensile stress under high cycle conditions was investigated. The microstructures of the AZ91 base material, MAO/AZ91 and MAO-epoxy/AZ91 samples, which were subjected to high-cycle fatigue tests and uniaxial static tensile tests, were assessed through the scanning electron microscope (SEM), X-ray diffraction (XRD) mechanical tests, and fatigue and tensile tests. As a result, the MAO-epoxy duplex coating, which has a homogeneous and compact structure, was observed to improve the fatigue limit value/life, yield strength, ultimate tensile strength, and percentage elongation values of the base material significantly.
- MakaleAçık Erişim2022Investigation of biodegradability of doped composite oxide coated AZ91 alloy in blood plasma; [Katkili oksit kaplamasi büyütülen AZ91 alaşiminin kan plazmasi içerisindeki biyoçözünürlüǧünün incelenmesi]
Şüküroǧlu, Ebru Emine; Çelik, Ayşenur
Magnesium alloys; It is widely used in metallic biomaterials with its low toxic effect and biodegradability. Although these alloys help the formation of new tissues in the body, they provide great advantages over other metallic biomaterials due to their ability to dissolve from the body after the area of use has healed. However, due to their low corrosion resistance, they cause it to dissolve in the body before the treatment process is completed. This is the major disadvantage that limits the use of magnesium alloys. Various surface modification methods are applied to magnesium alloys in order to eliminate this disadvantage. Micro Arc Oxidation (MAO) method, which can provide a coating resistant to wear and corrosion, is one of the surface modification methods applied to improve the surface properties of magnesium alloys. In this study; Composite oxide coatings with Ag nanoparticle and Hydroxyapatite were grown by MAO method. Morphological properties of the coatings were determined by Scanning electron microscope and X-Ray Diffraction instruments. The antibacterial properties of Ag nanoparticle and HA doped composite oxide layer which were grown by MAO method and the biodegradability of the coated/uncoated materials in the blood plasma were investigated. As a result of the experiments, the development of bacterial activity in the sample coated by MAO was prevented by adding Ag nanoparticle and Hydroxyapatite to the electrolite solution. In addition, the biodegradation rate has been reduced by surface treatment on AZ91 Mg Alloy. As a result of the soaking test in blood plasma, it was determined that AZ91 Mg alloy protects itself against dissolution with a rate of approximately 89%.
- BildiriAçık Erişim2021Investigation of In-Vitro Properties of NiTi Alloy After Micro Arc Oxidation
Süküroglu, Suleyman; Totik, Yapr; Süküroglu, Ebru Emine; Küçükosman, Ridvan
As material science is integrated into medical science as in other fields, the variety, development and usage areas of biomaterials increase. One of the biomaterials in this variety is NiTi alloys. This study was focused on the coating of TiO2 layer by using the method of Micro Ark Oxidation with the aim of the improvement of surface and mechanical properties of Shapedmemory and bio material NiTi alloy. Structural properties of the coatings were analysed by of SEM and XRD. In vitro ability was investigated by soaking the coated NiTi samples in simulated body fluid (SBF) at temperature 37 degrees C for various time periods. After soaking, Ni+2 release was applied to the media where coated and uncoated shape-memory NiTi samples are available, and its control was made by means of ICP-MS device. The results also show that Toxic and carcinogenic effects of Ni+2 release is significantly reduced by the TiO2 coating. Thus, it is observed that the properties that limit the use of NiTi alloys has been substantially fixed by MAO coating. It was found that the bioactive properties of the TiO2 coated NiTi substrate increased by MAO method and at the end of the 72 hour, there was no statistically any cytotoxicity in cell viability compared to the NiTi substrate.
- BildiriYalnız künye2011Hydroxyapatite 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.