Síntese e caracterização da estrutura cristalina de ferritas do tipo MXMn1-XFe2O4 (M = Co, Cu, Ba e X = 0,0;0,2) obtidas pelo método de co-precipitação
This study aimed to the synthesis of nano ferrites type MxMn1-xFe2O4 (M = Co, Cu e Ba e x = 0,0 e 0,2) by a synthetic route of co-precipitation, and study of the materials obtained by Diffraction X-ray (XRD), Scanning Electron Microscopy (SEM) and structural refinement of the phases obtained by the...
| Autor principal: | Pinto, Cristian de Souza |
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| Formato: | Trabalho de Conclusão de Curso (Graduação) |
| Idioma: | Português |
| Publicado em: |
Universidade Tecnológica Federal do Paraná
2020
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.utfpr.edu.br/jspui/handle/1/15353 |
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| Resumo: |
This study aimed to the synthesis of nano ferrites type MxMn1-xFe2O4 (M = Co, Cu e Ba e x = 0,0 e 0,2) by a synthetic route of co-precipitation, and study of the materials obtained by Diffraction X-ray (XRD), Scanning Electron Microscopy (SEM) and structural refinement of the phases obtained by the Rietveld method. XRD analysis of the synthesized material showed the spinel phase to obtain all samples and secondary phases CuFeO2 and BaCO3 in the samples containing copper and barium respectively. Images obtained by SEM showed agglomeration of particles, poly crystallinity and nano and micro dimensions for all samples. The structural refinement by the Rietveld method of spinels and obtained secondary phases showed cell dimensions a = b = c for the spinels, indicating a cubic system, and a = b ≠ c to the hexagonal phase CuFeO2 and a ≠ b ≠ c for orthorhombic phase BaCO3, indicating agreement to all crystalline systems. Differences in cell parameters observed for spinel can be justified by the difference of ionic radii of Mn2+ and Co2+ in the case of ferrite with addition of cobalt, and lack of ions in the spinel non stoichiometric obtained in the sample with barium. For the sample containing copper was observed an increase in cell parameters, a fact can be associated with Jahn-Teller distorting effects with Cu2+, which still reflect on a larger value in the network stress parameter in the spinel sample when compared with the other due to occupation of octahedral sites by copper. As observed in the literature, decreases in the spinel cell parameters reflected in a shift in the positions of the diffraction peaks to the right and an increase in cell parameters reflected in a shift to the left with respect to diffraction peaks of the spinel ferrite pure (x = 0.0) in the value of 2θ. The crystallite size values obtained by structural refinement showed that the particles all materials have nano dimensions and observed by SEM with micro dimensions are actually agglomerates of nanoparticles. |
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