Fabricação e caracterização de ferritas moles, duras e sua mistura

• Autor(a) principal: Xavier, Julia Cezaroni [UNESP]
• Data de Publicação: 2017
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/156806; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2018-08-16/000902380.pdf
• topic: Material cerâmico; Ferrita (Materiais magneticos); Materiais magneticos; Cerâmica; Pó de cerâmica; Ceramic materials

This work of conclusion of course proposes the study of different ferrites and their mixtures. The structural behavior of hard ferrites (BaFe12O19) and soft ferrites (ZnFe2O4) and their mixture in the same proportion (50% BaFe12O19 + 50% ZnFe2O4) was studied. For a manufacturing of the ceramics it was used the solid state reaction method, which presents a lot of advantages, such as: large-scale production and easy execution. The X-ray diffractograms revealed as present phases and the characteristic peaks of each ferrite, thus enabling a phase analysis. An all-phases extraction as samples (barium ferrite, zinc ferrite and mixed ferrite) was given by calcining at 950° C for 10 hours in a conventional oven. After sintering, we evaluated the density of the samples using the gas pycnometry technique, with a view to the sintering condition more suitable to maximize the density at 1200° C for 2 hours for all the samples. A microstructural analysis allowed to evaluate the average grain size through the intercepts method. In this way, it was obtained that the barium ferrite presents average grain size in magnitude of 0.47 μm, a ferrite of zinc 1.74 μm and finally the ferrite 0.66 μm. Knowing that the chemical substance, method of preparation and microstructure of the material are related to its properties, it is evaluated that as electrical properties obtained correspond to a microstructure of the material, since it is a barium ferrite by suggestion of grain contours, polarization terms in minors; while a zinc ferrite has a larger average grain size and presents an occurrence of polarization mechanisms at higher frequencies. The mixed ferrite presents intermediate properties both in relation to the frequency of occurrence of the polarization mechanisms and the average grain size