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Structure and properties of Hydroxyapatite-Magnesium composites produced by the means of current assisted infiltration sintering
Casas Luna, Mariano ; Obrtlík,, Karel (oponent) ; Georgarakis, Konstantinos (oponent) ; Čelko, Ladislav (vedoucí práce)
Magnesium and calcium phosphate composites are promising materials to create biodegradable and load-bearing implants for bone regeneration. The present work is focused on the design, processing and characterization of interpenetrated magnesium / calcium phosphate (Mg/CaP) composites. Calcium phosphates such as, hydroxyapatite (HA), calcium-deficient HA (CDHA) and tricalcium phosphate (TCP) were synthetized and used for the production of controlled porous scaffolds by means of robocasting technique. The final porous preforms with an orthogonal grid arrangement and internal macro-pores of ~500 µm were obtained and sintered at 1100 C for 5 h. The Mg/CaP interpenetrated composites were obtained by infiltrating the porous ceramic scaffolds with pure Mg and Mg alloys containing low amounts of calcium or zinc, i.e. Mg – 0.2 wt.% Ca and Mg – 1 wt.% Zn. The infiltration was carried out using a here-developed and recently introduced technique referred to as Current-Assisted Metal Infiltration (CAMI). The CAMI methodology allowed the infiltration of porous ceramic preforms with a molten metal in less than 15 minutes. Fast melting and final solidification of the Mg/CaP composites was achieved with the assistance of pulsed electrical current. The final interpenetrated composites were physicochemically characterized by means of scanning electron microscopy, X-ray computed micro-tomography, X ray diffraction and optical microscopy in order to determine the phase distribution and the interaction between the materials. In addition, the mechanical resistance under compression, the degradation rate by different techniques, and the biocompatibility of the produced composites were evaluated in an attempt to introduce these types of materials as potential degradable biomaterials for use in the manufacturing of plates and/or screws for orthopaedics.
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Structure and properties of Hydroxyapatite-Magnesium composites produced by the means of current assisted infiltration sintering
Casas Luna, Mariano ; Obrtlík,, Karel (oponent) ; Georgarakis, Konstantinos (oponent) ; Čelko, Ladislav (vedoucí práce)
Magnesium and calcium phosphate composites are promising materials to create biodegradable and load-bearing implants for bone regeneration. The present work is focused on the design, processing and characterization of interpenetrated magnesium / calcium phosphate (Mg/CaP) composites. Calcium phosphates such as, hydroxyapatite (HA), calcium-deficient HA (CDHA) and tricalcium phosphate (TCP) were synthetized and used for the production of controlled porous scaffolds by means of robocasting technique. The final porous preforms with an orthogonal grid arrangement and internal macro-pores of ~500 µm were obtained and sintered at 1100 C for 5 h. The Mg/CaP interpenetrated composites were obtained by infiltrating the porous ceramic scaffolds with pure Mg and Mg alloys containing low amounts of calcium or zinc, i.e. Mg – 0.2 wt.% Ca and Mg – 1 wt.% Zn. The infiltration was carried out using a here-developed and recently introduced technique referred to as Current-Assisted Metal Infiltration (CAMI). The CAMI methodology allowed the infiltration of porous ceramic preforms with a molten metal in less than 15 minutes. Fast melting and final solidification of the Mg/CaP composites was achieved with the assistance of pulsed electrical current. The final interpenetrated composites were physicochemically characterized by means of scanning electron microscopy, X-ray computed micro-tomography, X ray diffraction and optical microscopy in order to determine the phase distribution and the interaction between the materials. In addition, the mechanical resistance under compression, the degradation rate by different techniques, and the biocompatibility of the produced composites were evaluated in an attempt to introduce these types of materials as potential degradable biomaterials for use in the manufacturing of plates and/or screws for orthopaedics.
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