Estudo das propriedades dielétricas e magnéticas da hexaferrita Ba2Co2Fe12O22 (Co2Y) adicionadas com PbO E Bi2O3 para aplicação em dispositivos de RF e micro-ondas.

• Autor(a) principal: Pires Júnior, Guilherme Francisco de Morais
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/60149
• topic: Hexaferritas; Cerâmicas magnéticas; Síntese de estado sólido

The increasing development of the industry of telecommunications demands the incessant study and the later manufacture of passive electronic devices of miniaturization, with high electromagnetic performance and trustworthiness, beyond low cost. All these requirements are for guaranteeing communication systems that operate adequately in well definite frequencies, which these electronic devices if consider to operate. In last the 60 years the magnetic ceramics (hexaferrites) if had consolidated and become very attractive for use in these electronic devices that demand great efficiency. The ceramics currently offer significant advantages for presenting low cost of production for electronic devices that operate in radio frequency (RF) and microwaves, beyond being material of low weight, steady with the temperature and extremely liabilities of miniaturization (compacting). The magnetic ceramics also possess lesser dielectric losses, and are preferred in many of the current technological applications. This work is divided in two stages. The first one consists of getting the magnetic ceramics (hexaferrite) Ba2Co2Fe12O22 (Co2Y) through of the solid-state synthesis with milling mechanics of high energy and the second is to study the dielectric properties of a series of the material Ba2Co2Fe12O22 added with lead oxide (PbO) and bismuth oxide (Bi2O3) and to discuss the influence of the concentration of these oxides and of the binders PVA (polyvinyl alcohol) and TEOS (Tetraetilortosilicate). The X-ray Diffraction (XRD) was essential in the work for structural characterization of the desired ceramic. The morphology of the samples was studied by the Scanning Electron Microscopy (SEM). And experiments had been additionally carried through to evaluate the dielectric and magnetic performance of the species in study in the radio and microwaves range frequency for later analysis of an appropriate technological application. The experiments showed that the addition of PbO and Bi2O3 lead to higher values of dielectric permittivity and lower dielectric losses for Co2Y in RF and microwave, which is more compact (miniaturize) and efficient devices designed to operate on those frequencies respectively.