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Hydroxyapatite based ceramic composites
Vojtíšek, Jan ; Ptáček, Petr (referee) ; Bartoníčková, Eva (advisor)
This work was focused on the study of hydroxyapatite based bioceramic materials. These materials are generally very important for medical purposes, especially in the reconstruction and replacement of bone material. For medical applications, inert, bioactive or bioresorbable materials can be used. One of the common "bioactive" materials is hydroxyapatite, which forms a large part of human bone. Hydroxyapatite can be prepared by a wide variety of procedures, one of the most common methods is the precipitation reaction used in this work. To improve the biocompatibility of the bone replacement, porous structures with adequate mechanical stability are used. For the initial study of simulation of the behavior of biomaterials in the human body, called in vitro tests are used in solutions based on synthetic body fluids or cell media. The experimental part deals with the synthesis of hydroxyapatite powder and CA phase composite compounds. The reactions between the individual components were studied by thermal analysis and heat microscopy. The resulting products were analyzed for phase composition by X-ray diffraction. The prepared powders were further processed on foam structures by in situ foaming and sintering at a suitable temperature. In vitro tests, following the behavior of the prepared porous products in the synthetic body fluid, were performed for 7, 14 and 28 days. The monitored composites were then studied for biocompatibility by scanning electron microscopy. At the same time, the change in the concentration of Ca2+ and PO43- ions in the body fluids tested was monitored.
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Hydroxyapatite based ceramic composites
Vojtíšek, Jan ; Ptáček, Petr (referee) ; Bartoníčková, Eva (advisor)
This work was focused on the study of hydroxyapatite based bioceramic materials. These materials are generally very important for medical purposes, especially in the reconstruction and replacement of bone material. For medical applications, inert, bioactive or bioresorbable materials can be used. One of the common "bioactive" materials is hydroxyapatite, which forms a large part of human bone. Hydroxyapatite can be prepared by a wide variety of procedures, one of the most common methods is the precipitation reaction used in this work. To improve the biocompatibility of the bone replacement, porous structures with adequate mechanical stability are used. For the initial study of simulation of the behavior of biomaterials in the human body, called in vitro tests are used in solutions based on synthetic body fluids or cell media. The experimental part deals with the synthesis of hydroxyapatite powder and CA phase composite compounds. The reactions between the individual components were studied by thermal analysis and heat microscopy. The resulting products were analyzed for phase composition by X-ray diffraction. The prepared powders were further processed on foam structures by in situ foaming and sintering at a suitable temperature. In vitro tests, following the behavior of the prepared porous products in the synthetic body fluid, were performed for 7, 14 and 28 days. The monitored composites were then studied for biocompatibility by scanning electron microscopy. At the same time, the change in the concentration of Ca2+ and PO43- ions in the body fluids tested was monitored.
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Effect of coating on fracture behaviour of ceramic foams under tensile loading
Řehořek, Lukáš ; Dlouhý, Ivo ; Chlup, Zdeněk
Cellular structures are promising type of architecture for a lot of materials whether made of metals, plastic or ceramic. Target applications are those where lightweight, damping and and/or stiff properties are required. With combination of different kinds of materials the foamed composites with favourable mechanical properties can be developed. In case of ceramic foams the main disadvantage – brittleness – can be reduced. For straight forward application of this materials all types of mechanical properties have to be known. The tensile properties of open cell ceramic foam material based on alumina coated by various materials are presented in this paper.
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Fracture behaviour of ceramic cellular solids under tensile loading
Řehořek, Lukáš ; Dlouhý, Ivo ; Chlup, Zdeněk
Cellular structures are promising type of architecture for a lot of materials whether made of metals, plastic or ceramic aimed at applications where lightweight, damping and and/or stiff properties are required. For trouble-free use of this materials all types of mechanical behaviour have to be known. The tensile tests of open cell ceramic foam material based on alumina are presented in this paper and complemented of acoustic emission data and digital image correlation for measuring deformations. From the results follows that ceramic foams under tensile loading behave significantly different from widely used compressive or bending tests.
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