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Bioactivity Properties and Characterization of Commercial Synthetic Hydroxyapatite - 5 wt.% Niobium (V) Oxide - 5 wt.% Magnesium Oxide Composite

100%
Demirkol N.
Acta Physica Polonica A
|
2017
|
vol. 132
|
issue 3
786-788
EN
Hydroxyapatite is widely used for bone grafts due to its chemical and structural similarities to the mineral phase of hard tissues and due to its bioactivity and biocompatibility. However, hydroxyapatite has poor mechanical properties due to its brittleness. To improve mechanical properties of hydroxyapatite-ceramics, ceramic oxides, whiskers or fibers have been suggested. In this study, commercial synthetic hydroxyapatite composite reinforced with 5 wt.% Nb₂O₅ and 5 wt.% MgO was characterized. Microstructural properties of all samples sintered at different temperatures were characterized using scanning electron microscopy technique. Phase analysis was carried out using X-ray diffraction technique. Mechanical properties were measured by compression and hardness tests. The bioactivity property was determined by in vitro bioactivity test. The best obtained values of density, compression strength and Vickers Microhardness were 3.01 g/cm³, 96 MPa and 393 HV, for composite sintered at 1300°C for 4 hours. Bioactivity results for composite, sintered at 1300°C, show that apatite formation has started after two weeks in a simulated body fluid. At the end of the fourth week, the dense apatite layer and clusters were observed on the surface of the composite.
2
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Influence of Commercial Inert Glass Addition οn the Mechanical Properties οf Commercial Synthetic Hydroxyapatite

51%
Demirkol N., Nuzhet Oktar F., Sabri Kayali E.
Acta Physica Polonica A
|
2013
|
vol. 123
|
issue 2
427-429
EN
In this study, microstructures and mechanical properties of commercial synthetic hydroxyapatite (CSHA)-commercial inert glass (CIG) composites were investigated. The goal of development of CSHA-CIG composite is to improve mechanical properties of hydroxyapatite. For this reason, CSHA powders were mixed with 5 and 10 wt% CIG separately. Pressed samples were sintered at the different temperatures in the range of 1000-1300°C. The physical and mechanical properties were determined by measuring density, compression strength, the Vickers microhardness. Structural characterization was carried out with X-ray diffraction and scanning electron microscopy studies. The experimental results were discussed to determine optimum amount of reinforcement material and the effect of sintering temperature on the microstructure and the mechanical properties of CSHA-CIG composites. The mechanical properties of composites decreased with increasing CIG content. The highest mechanical properties and the highest density were obtained in CSHA-5 wt%CIG composite sintered at 1300C.
3
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Mechanical and Microstructural Properties of Sheep Hydroxyapatite (SHA)-Niobium Oxide Composites

51%
Demirkol N., Oktar F., Kayali E.
Acta Physica Polonica A
|
2012
|
vol. 121
|
issue 1
274-276
EN
The aim of this study is to produce and to investigate the mechanical and microstructural properties of composite materials made of hydroxyapatite, obtained from natural sheep bone and niobium oxide (5 and 10 wt%). Sheep hydroxyapatite (SHA) matrix was reinforced with 5 and 10 wt% of niobium (Nb) oxide powder. The calcinated SHA was ball milled separately with 5% and 10% niobium oxide for 4 h. The samples were subjected to sintering at different temperatures between 1000C and 1300°C. The mechanical properties were determined by measuring compression strength and Vickers microhardness (HV). X-ray diffraction and scanning electron microscopy studies were carried out to analyze the microstructure. With increasing sintering temperature, mechanical properties of composites increased. The SHA-composites with 10 wt% niobium oxide addition had better mechanical properties at all sintering temperatures. The highest mechanical properties were obtained in SHA-10 wt% niobium oxide composite sintered at 1300°C. Adding of niobium oxide to SHA could be a valuable method to produce rigid and high load carrying ability HA composite which is suitable for orthopedic applications.
4
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Comparison of Microstructural and Mechanical Properties of Hydroxyapatite-Al₂O₃ Composites with Commercial Inert Glass (CIG) Addition

51%
Bulut B., Demirkol N., Erkmen Z., Kayali E.
Acta Physica Polonica A
|
2015
|
vol. 127
|
issue 4
1094-1096
EN
Hydroxyapatite (HA) is one of the most widely used biomaterials for orthopedic and dental applications. However, HA is a brittle and weak material and this constrains its orthopedic applications. There are several methods for the improvement of mechanical properties of the HA. One of these methods is to strengthen the HA material by a secondary phase (i.e polymer, metal or ceramics), to make a stronger composite material. Alumina (Al₂O₃) is a bioinert material, which has been widely investigated as a reinforcing agent for HA. The aim of this study is to compare the microstructural and mechanical properties of HA-Al₂O₃ composites with the addition of 5 and 10 wt.% of commercial inert glass (CIG). The grain samples were produced according to BS 7253 at 350 MPa. Then, they were sintered at temperatures between 1000-1300°C for 4 hours. The samples were also analyzed by SEM + EDS to determine microstructural properties, phase analysis was done by X-ray diffractometer (XRD), mechanical properties were measured by compression and hardness tests. Results show that HA-Al₂O₃ composites with addition of 5 and 10 wt.% CIG have reached high density values and high mechanical properties, such as compression strength and hardness at 1300°C. The compression strength and hardness of composites has increased with the increasing CIG content.
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