Made available in DSpace on 2014-12-17T15:41:56Z (GMT). No. of bitstreams: 1 ManuellaKCR_DISSERT.pdf: 3952261 bytes, checksum: 56cf586893164ffedc3ec29beb8e775a (MD5) Previous issue date: 2010-08-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Were synthesized ferrites of NiZn on systems Ni0,5Zn0,5Fe2O4, the precursors citrate method. The decomposition of the precursors was studied by thermogravimetric analysis and spectroscopy in the infrared region, the temperature of 350?C/3h. The evolution of the phases formed after calcinations at 350?C/3h, 600, 1000 and 1100?C/2h was accompanied by X-ray diffraction using the Rietveld refinement method for better identification os structures formed. Was observed for samples calcined at different temperatures increased crystallinity with increasing calcination temperature, being observed for the samples calcined at 900 and 1100 ? C/2h was the precipitation of a secondary phase, the phase hematite. The ferrocarbonila of industrial origin was analyzed by X-ray diffraction and Rietveld for the identification of its structure. The carbonyl iron was added NiZn ferrite calcined at 350?C/3h, 600, 900, 1000 and 1100?C/2h to the formation of hybrid mixtures. They were then analyzed by Xray diffraction and Rietveld. The NiZn ferrite and ferrocarbonila as well as the hybrid mixtures were subjected to analysis of scanning electron microscopy, magnetic measurements and reflectivity. The magnetic measurements indicated that the ferrite, the ferrocarbonila, as well as hybrid mixtures showed characteristics of soft magnetic material. The addition of ferrocarbonila in all compositions showed an increase in the results of magnetic measurements and reflectivity. Best result was observed in the increase of the magnetization for the hybrid mixture of Ferrocarbonila / ferrite of NiZn calcined at 600?C/2h. The mixture Ferrocarbonila / ferrite calcined 1000?C/2h presented better absorption of electromagnetic radiation in the microwave / Foram sintetizadas ferritas de NiZn no sistema Ni0,5Zn0,5Fe2O4, pelo m?todo dos citratos precursores. A decomposi??o dos precursores foi estudada por an?lise termogravim?trica e espectroscopia na regi?o do infravermelho na temperatura de 350?C/3h. A evolu??o das fases formadas ap?s calcina??es a 350?C/3h, 600, 1000 e 1100?C/2h foi acompanhada por difra??o de raios X utilizando o refinamento de Rietveld para melhor identifica??o das estruturas formadas. Foi observado para as amostras calcinadas em diferentes temperaturas o aumento da cristalinidade com o aumento da temperatura de calcina??o, sendo verificado que para as amostras calcinadas a 900 e 1100?C/2h ocorreu a precipita??o de uma fase secund?ria, a fase hematita. A ferrocarbonila de proced?ncia industrial foi analisada por Difra??o de raios X e por Rietveld para a identifica??o de sua estrutura. A ferrocarbonila foi adicionada ? ferrita de NiZn calcinada a 350?C/3h, 600, 1000 e 1100?C/2h para a forma??o das misturas h?bridas. Em seguida foram analisadas por difra??o de raios X e por Rietveld. A ferrita de NiZn, a ferrocarbonila, assim como as misturas h?bridas foram submetidas ? an?lises de Microscopia Eletr?nica de Varredura, medidas magn?ticas e refletividade. As medidas magn?ticas indicaram que a ferrita, a ferrocarbonila, como tamb?m as misturas h?bridas apresentaram caracter?sticas de material magn?tico macios. A adi??o de ferrocarbonila em todas as composi??es indicou um aumento nos resultados de medidas magn?ticas e de refletividade. Foi verificado melhor resultado no aumento da magnetiza??o para a mistura h?brida de Ferrocarbonila/ferrita de NiZn calcinada 600?C/2h. A mistura Ferrocarbonila/ferrita calcinada 1000?C/2h apresentou melhor resultado absor??o da radia??o eletromagn?tica na faixa de microondas em rela??o ?s outras misturas