Detalhes bibliográficos
Ano de defesa: |
2011 |
Autor(a) principal: |
Moreira, Mirna Pereira
 |
Orientador(a): |
Santos, Euler Araujo dos
 |
Banca de defesa: |
Não Informado pela instituição |
Tipo de documento: |
Dissertação
|
Tipo de acesso: |
Acesso aberto |
Idioma: |
por |
Instituição de defesa: |
Universidade Federal de Sergipe
|
Programa de Pós-Graduação: |
Pós-Graduação em Ciência e Engenharia de Materiais
|
Departamento: |
Não Informado pela instituição
|
País: |
BR
|
Palavras-chave em Português: |
|
Palavras-chave em Inglês: |
|
Área do conhecimento CNPq: |
|
Link de acesso: |
https://ri.ufs.br/handle/riufs/3513
|
Resumo: |
The main objective of this work was investigating the physic-chemical effects of the individual and simultaneous replacement of Ca2+ ions for Mg2+, Sr2+ and Mn2+ onto the crystalline structure of hydroxyapatite (HA). The X-ray analyses indicated that the substitution of Ca2+ for other ions after synthesis caused a remarkable decreasing of the crystallinity index comparatively to the pure HA. The lattice parameters revealed that the addition of Mg2+ and Mn2+ lead to a slight reduction of the cell unit volume. After calcination, o Mn2+ changed its oxidation state being introduced at the PO4 3- sites as MnO4 3- groups. The thermal treatment strongly increased the crystallite growth for all samples, and also promoted the change from elongated crystals before calcination to spherical ones after calcination. The simultaneous insertion of three ions in the HA lattice seemed generate a favorable situation for organizing the apatite crystal once the crystallinity index was the highest among the samples and the measured lattice parameters were quite close to those calculated to the pure HA. The samples containing Sr2+ ((HA-Sr e HA-Mn/Sr/Mg) were denser than those containing Mg2+ (HA-Mg) and Mn2+ (HA-Mn). However, the HA-Sr was more soluble than HA-Mn or HA-Mg. The use of three elements with different ionic radii in substitution to the Ca2+ allowed the creation of a new HA ceramic with a high level of crystallinity and a satisfactory thermal stability for applying in the production of bioceramic devices. |