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Processing and characterization of ceramics based hydroxyapatite and tricalcium phosphate

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Ribeiro, Christiane
Total Authors: 1
Document type: Master's Dissertation
Press: São Paulo. [2003]. 101 f., ilustrações, tabelas.
Institution: São Paulo (Estado). Secretaria de Desenvolvimento. Instituto de Pesquisas Energéticas e Nucleares (IPEN)
Defense date:
Examining board members:
Bressiani, Ana Helena de Almeida; Rigo, Eliana Cristina da Silva; Yoshimura, Humberto Naoyuki
Advisor: Bressiani, Ana Helena de Almeida
Field of knowledge: Engineering - Materials and Metallurgical Engineering
Indexed in: Base de dados PHL Elysio - Rede de Bibliotecas da CNEN
Location: Instituto de Pesquisas Energéticas e Nucleares. Biblioteca Terezine Arantes Ferraz; T61; R484p

Calcium phosphate bioactive and resorbable ceramics find an infinity ofapplications in the medical area, such as bone substitutes due to its biocompatibility and osteoconducfion capacity, which enable cell proliferation on the surface of these materials and in complex drugs delivery systems. In this work, samples were prepared usinghydroxyapatite (Hap), P-tricalcium phosphate (TCP) and biphasic ceramics (Hap/TCP) in different ratios. Starting materials were characterized by X-ray diffractometry (XRD), particle size distribution by laser diffraction, specific surface area by BET, infrared spectroscopy (FTIR) and of inductively coupled plasma atomic emission spectroscopy (ICP-AES) and by scanning electron microscopy (SEM). The powders of HAp, TCP andtheir mixtures were homogeneized, uniaxially and cold isostatically pressed (200 MPa) into cylindrical green bodies of 7 and 12 mm. Parameters of sintering in oxidative atmosphere furnace were defined after dilatometric studies. The samples exhibited highdegree of shrinkage during sintering wich enable to achieve high final densities (~ 95% pt). The densification increases with the decreasing of TCP content. The sintered samples were characterized by XRD and SEM. Formation of other phases weren't detected in any of the sintered samples. The dissolution kinetics and in vitro reactivity of ceramics were investigated using simulated body fluid (SBF) at 37°C for 3 weeks. The dissolution studywas investigated by means of pH and neutron activation analysis (NAA) to calcium quantitative analysis, of the solutions and weight variation of the samples. The surfaces of the samples were investigated by FTIR and SEM-EDS. The results of dissolution demonstrated that TCP ceramics show dissolution kinetics quicker than the other samples, and biphasic ceramics demonstrated major tendency to the formation of the hydroxycarbonateapatite (HCA) layer within the immersion period. (AU)