Investigação teórica e experimental das propriedades elétricas em alta frequência da matriz CoTiO3 e os efeitos da adição de V2O5

• Ano de defesa: 2020
• Autor(a) principal: Silva, Raquel Abreu da
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Cerâmicas; Titanato de cobalto; Óxido de vanádio; Micro-ondas; Radiofrequência
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/55483

With the increasing technological development in the area of ceramic materials, there is great interest in the potential applications of these materials in microwave and radiofrequency (RF). This work aims to synthesize the cobalt titanate (CoTiO3) ceramics and to evaluate its dielectric properties after adding vanadium oxide (V2O5) with variations of 5, 10 and 20 percent by mass. For this the solid state reaction method was used, with high energy mechanical milling and sintering after grinding. The structural and morphological characteristics were performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM), which confirmed the formation of the CoTiO3 phase and also revealed that the addition of V2O5 promoted the formation of secondary phases. The results of impedance spectroscopy showed that addition of V2O5 increased the values of impedance and dielectric permittivity as well as a decrease in the dielectric loss of the composites. The microwave study revealed a small increase in permittivity and low loss (tgδ), ranging from 10-4 to 10-2 . The CoTO-10 sample presented τf +2.13 (ppm / ° C), presenting good thermal stability. At the end of the analysis of the DRA, it can be seen that CoTO10 presented the best set of parameters of distant field as a good efficiency, better gain and a good directivity.