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Laura Montanaro - One of the best experts on this subject based on the ideXlab platform.
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f substituted Hydroxyapatite nanopowders thermal stability sintering behaviour and mechanical properties
Ceramics International, 2010Co-Authors: Alessandra Bianco, Ilaria Cacciotti, Mariangela Lombardi, Laura Montanaro, Edoardo Bemporad, Marco SebastianiAbstract:Abstract Fluorine-substituted Hydroxyapatites are considered promising materials for bone scaffolding. In this study a systematic investigation on F-half substituted Hydroxyapatite (F-HAp, Ca10(PO4)6OHF) obtained by precipitation is reported. Results on composition analysis, thermal behaviour, and sinterability are presented for a comparison with the respective pure Hydroxyapatite. Samples were characterised by electron microscopy, induced coupled plasma-atomic emission spectroscopy, thermal analysis, infrared spectroscopy, N2 adsorption measurements, X-ray diffraction and dilatometry. A semicrystalline F-substituted Hydroxyapatite powder made up of needle-like nanoparticles was obtained. Notwithstanding that it was thermally stable up to 1300 °C, it was sintered at relatively low temperatures obtaining a very fine microstructure with a relevant nano-porosity, beneficial in view of cell adhesion and in-growth. Hardness, elastic modulus and toughness of produced samples were investigated by Vickers–Knoop microhardness testing. Significant improvements of the mechanical properties were observed for the F-substituted Hydroxyapatite, in comparison with pure Hydroxyapatite.
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mg substituted Hydroxyapatite nanopowders synthesis thermal stability and sintering behaviour
Journal of The European Ceramic Society, 2009Co-Authors: Ilaria Cacciotti, Alessandra Bianco, Mariangela Lombardi, Laura MontanaroAbstract:Abstract This paper reports a systematic investigation on Mg-substituted Hydroxyapatite (Ca 10− x Mg x (PO 4 ) 6 (OH) 2 ) nanopowders produced by precipitation of Ca(NO 3 ) 2 ·4H 2 O and Mg(NO 3 ) 2 . The Mg content ranged between 0.6 and 2.4 wt%. Semicrystalline Mg-substituted Hydroxyapatite powders made up of needle-like nanoparticles were obtained, the specific surface area ranged between 87 and 142 m 2 /g. Pure Hydroxyapatite nanopowder decomposed around 1000 °C. Mg-substituted Hydroxyapatites were thermally stable up to 660 °C ( x = 1.0), 760 °C ( x = 0.5) and 840 °C ( x = 0.25) showing a distinct decreased thermal stability with respect to the pure sample. A relevant displacement of the sintering curve at lower temperature as a function of Mg content was observed, comparing to the behaviour of a pure HAp material, synthesized following the same procedure, and ascribed to the β-TCP formation.
Ilaria Cacciotti - One of the best experts on this subject based on the ideXlab platform.
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f substituted Hydroxyapatite nanopowders thermal stability sintering behaviour and mechanical properties
Ceramics International, 2010Co-Authors: Alessandra Bianco, Ilaria Cacciotti, Mariangela Lombardi, Laura Montanaro, Edoardo Bemporad, Marco SebastianiAbstract:Abstract Fluorine-substituted Hydroxyapatites are considered promising materials for bone scaffolding. In this study a systematic investigation on F-half substituted Hydroxyapatite (F-HAp, Ca10(PO4)6OHF) obtained by precipitation is reported. Results on composition analysis, thermal behaviour, and sinterability are presented for a comparison with the respective pure Hydroxyapatite. Samples were characterised by electron microscopy, induced coupled plasma-atomic emission spectroscopy, thermal analysis, infrared spectroscopy, N2 adsorption measurements, X-ray diffraction and dilatometry. A semicrystalline F-substituted Hydroxyapatite powder made up of needle-like nanoparticles was obtained. Notwithstanding that it was thermally stable up to 1300 °C, it was sintered at relatively low temperatures obtaining a very fine microstructure with a relevant nano-porosity, beneficial in view of cell adhesion and in-growth. Hardness, elastic modulus and toughness of produced samples were investigated by Vickers–Knoop microhardness testing. Significant improvements of the mechanical properties were observed for the F-substituted Hydroxyapatite, in comparison with pure Hydroxyapatite.
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mg substituted Hydroxyapatite nanopowders synthesis thermal stability and sintering behaviour
Journal of The European Ceramic Society, 2009Co-Authors: Ilaria Cacciotti, Alessandra Bianco, Mariangela Lombardi, Laura MontanaroAbstract:Abstract This paper reports a systematic investigation on Mg-substituted Hydroxyapatite (Ca 10− x Mg x (PO 4 ) 6 (OH) 2 ) nanopowders produced by precipitation of Ca(NO 3 ) 2 ·4H 2 O and Mg(NO 3 ) 2 . The Mg content ranged between 0.6 and 2.4 wt%. Semicrystalline Mg-substituted Hydroxyapatite powders made up of needle-like nanoparticles were obtained, the specific surface area ranged between 87 and 142 m 2 /g. Pure Hydroxyapatite nanopowder decomposed around 1000 °C. Mg-substituted Hydroxyapatites were thermally stable up to 660 °C ( x = 1.0), 760 °C ( x = 0.5) and 840 °C ( x = 0.25) showing a distinct decreased thermal stability with respect to the pure sample. A relevant displacement of the sintering curve at lower temperature as a function of Mg content was observed, comparing to the behaviour of a pure HAp material, synthesized following the same procedure, and ascribed to the β-TCP formation.
Alessandra Bianco - One of the best experts on this subject based on the ideXlab platform.
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f substituted Hydroxyapatite nanopowders thermal stability sintering behaviour and mechanical properties
Ceramics International, 2010Co-Authors: Alessandra Bianco, Ilaria Cacciotti, Mariangela Lombardi, Laura Montanaro, Edoardo Bemporad, Marco SebastianiAbstract:Abstract Fluorine-substituted Hydroxyapatites are considered promising materials for bone scaffolding. In this study a systematic investigation on F-half substituted Hydroxyapatite (F-HAp, Ca10(PO4)6OHF) obtained by precipitation is reported. Results on composition analysis, thermal behaviour, and sinterability are presented for a comparison with the respective pure Hydroxyapatite. Samples were characterised by electron microscopy, induced coupled plasma-atomic emission spectroscopy, thermal analysis, infrared spectroscopy, N2 adsorption measurements, X-ray diffraction and dilatometry. A semicrystalline F-substituted Hydroxyapatite powder made up of needle-like nanoparticles was obtained. Notwithstanding that it was thermally stable up to 1300 °C, it was sintered at relatively low temperatures obtaining a very fine microstructure with a relevant nano-porosity, beneficial in view of cell adhesion and in-growth. Hardness, elastic modulus and toughness of produced samples were investigated by Vickers–Knoop microhardness testing. Significant improvements of the mechanical properties were observed for the F-substituted Hydroxyapatite, in comparison with pure Hydroxyapatite.
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mg substituted Hydroxyapatite nanopowders synthesis thermal stability and sintering behaviour
Journal of The European Ceramic Society, 2009Co-Authors: Ilaria Cacciotti, Alessandra Bianco, Mariangela Lombardi, Laura MontanaroAbstract:Abstract This paper reports a systematic investigation on Mg-substituted Hydroxyapatite (Ca 10− x Mg x (PO 4 ) 6 (OH) 2 ) nanopowders produced by precipitation of Ca(NO 3 ) 2 ·4H 2 O and Mg(NO 3 ) 2 . The Mg content ranged between 0.6 and 2.4 wt%. Semicrystalline Mg-substituted Hydroxyapatite powders made up of needle-like nanoparticles were obtained, the specific surface area ranged between 87 and 142 m 2 /g. Pure Hydroxyapatite nanopowder decomposed around 1000 °C. Mg-substituted Hydroxyapatites were thermally stable up to 660 °C ( x = 1.0), 760 °C ( x = 0.5) and 840 °C ( x = 0.25) showing a distinct decreased thermal stability with respect to the pure sample. A relevant displacement of the sintering curve at lower temperature as a function of Mg content was observed, comparing to the behaviour of a pure HAp material, synthesized following the same procedure, and ascribed to the β-TCP formation.
Mariangela Lombardi - One of the best experts on this subject based on the ideXlab platform.
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f substituted Hydroxyapatite nanopowders thermal stability sintering behaviour and mechanical properties
Ceramics International, 2010Co-Authors: Alessandra Bianco, Ilaria Cacciotti, Mariangela Lombardi, Laura Montanaro, Edoardo Bemporad, Marco SebastianiAbstract:Abstract Fluorine-substituted Hydroxyapatites are considered promising materials for bone scaffolding. In this study a systematic investigation on F-half substituted Hydroxyapatite (F-HAp, Ca10(PO4)6OHF) obtained by precipitation is reported. Results on composition analysis, thermal behaviour, and sinterability are presented for a comparison with the respective pure Hydroxyapatite. Samples were characterised by electron microscopy, induced coupled plasma-atomic emission spectroscopy, thermal analysis, infrared spectroscopy, N2 adsorption measurements, X-ray diffraction and dilatometry. A semicrystalline F-substituted Hydroxyapatite powder made up of needle-like nanoparticles was obtained. Notwithstanding that it was thermally stable up to 1300 °C, it was sintered at relatively low temperatures obtaining a very fine microstructure with a relevant nano-porosity, beneficial in view of cell adhesion and in-growth. Hardness, elastic modulus and toughness of produced samples were investigated by Vickers–Knoop microhardness testing. Significant improvements of the mechanical properties were observed for the F-substituted Hydroxyapatite, in comparison with pure Hydroxyapatite.
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mg substituted Hydroxyapatite nanopowders synthesis thermal stability and sintering behaviour
Journal of The European Ceramic Society, 2009Co-Authors: Ilaria Cacciotti, Alessandra Bianco, Mariangela Lombardi, Laura MontanaroAbstract:Abstract This paper reports a systematic investigation on Mg-substituted Hydroxyapatite (Ca 10− x Mg x (PO 4 ) 6 (OH) 2 ) nanopowders produced by precipitation of Ca(NO 3 ) 2 ·4H 2 O and Mg(NO 3 ) 2 . The Mg content ranged between 0.6 and 2.4 wt%. Semicrystalline Mg-substituted Hydroxyapatite powders made up of needle-like nanoparticles were obtained, the specific surface area ranged between 87 and 142 m 2 /g. Pure Hydroxyapatite nanopowder decomposed around 1000 °C. Mg-substituted Hydroxyapatites were thermally stable up to 660 °C ( x = 1.0), 760 °C ( x = 0.5) and 840 °C ( x = 0.25) showing a distinct decreased thermal stability with respect to the pure sample. A relevant displacement of the sintering curve at lower temperature as a function of Mg content was observed, comparing to the behaviour of a pure HAp material, synthesized following the same procedure, and ascribed to the β-TCP formation.
Iain Ronald Gibson - One of the best experts on this subject based on the ideXlab platform.
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Natural and Synthetic Hydroxyapatites
Biomaterials Science, 2020Co-Authors: Iain Ronald GibsonAbstract:Abstract Hydroxyapatite is a specific calcium phosphate phase that can occur naturally or can be synthesized using a variety of methods. Importantly it is similar in chemical and phase composition to the inorganic mineral component of bone and teeth. It has therefore been studied extensively as a biomaterial and has found applications alone or in combination with other materials to produce medical devices. This chapter reviews the various synthesis methods that have been utilised to produce Hydroxyapatite, including comparisons with naturally occurring Hydroxyapatites, the potential to substitute various ions in the Hydroxyapatite structure, and the ability to control physical properties of the resulting material, including porosity and crystallite size and morphology. It also includes a review of the various methods for characterising these materials, including chemical, physical and biological characterisation. Although Hydroxyapatite-based medical devices have been used clinically for many decades, it is clear that there is still much to learn about the factors such as composition and microstructure that can illicit various responses in vivo and how these may be best harnessed in the design of new materials for use as biomaterials.
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novel synthesis and characterization of an ab type carbonate substituted Hydroxyapatite
Journal of Biomedical Materials Research, 2002Co-Authors: Iain Ronald Gibson, W BonfieldAbstract:A novel synthesis route has been developed to produce a high-purity mixed AB-type carbonate-substituted Hydroxyapatite (CHA) with a carbonate content that is comparable to the type and level observed in bone mineral. This method involves the aqueous precipitation in the presence of carbonate ions in solution of a calcium phosphate apatite with a Ca/P molar ratio greater than the stoichiometric value of 1.67 for Hydroxyapatite (HA). The resulting calcium-rich carbonate–apatite is sintered/heat-treated in a carbon dioxide atmosphere to produce a single-phase, crystalline carbonate-substituted Hydroxyapatite. In contrast to previous methods for producing B- or AB-type carbonate-substituted Hydroxyapatites, no sodium or ammonium ions, which would be present in the reaction mixture from the sodium or ammonium carbonates commonly used as a source of carbonate ions, were present in the final product. The chemical and phase compositions of the carbonate-substituted Hydroxyapatite was characterized by X-ray fluorescence and X-ray diffraction, respectively, and the level and nature of the carbonate substitution were studied using C-H-N analysis and Fourier transform infrared spectroscopy, respectively. The carbonate substitution improves the densification of Hydroxyapatite and reduces the sintering temperature required to achieve near-full density by approximately 200°C compared to stoichiometric HA. Initial studies have shown that these carbonate-substituted Hydroxyapatites have improved mechanical and biologic properties compared to stoichiometric Hydroxyapatite. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 697–708, 2002
