In this paper the ceramic matrix of TiFeNbO6 (TFNO) was studied. The TFNO phase was calcined at 1,075 °C and used to prepare the samples, of 2, 4, 6, 8 and 10 wt% of the Bi2O3 and sintered at 1,125 °C. These samples were characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy and dielectric microwave properties. XRD and RS were used to characterize these samples. The samples presented two new phases. The first phase is the tetragonal rutile structure with a space group of P42/mnm, equivalent at parent rutile Ti0.4Fe0.3 Nb0.3O2 (TFNO) with 040725 ICSD code, and the secondary phase belonging to the pyrochlore system Bi1.721Fe1.056Nb1.134O7 (BFNO), with a space group of Fd-3mZ (227), in a cubic structure. The dielectric properties have shown significant variation for 10 % Bi2O3-added sample, because the formation of the new phase (BFNO) contributes with the reduction of τf from 281.12 to 77.45 ppm/°C and with increase in εr, from 47.23 to 63.77 and an increase in the dielectric loss (tan δ), from 0.0016 to 0.0068, respectively. Even though, Bi2O3 additive deteriorates the dielectric loss of the ceramics, the permittivity has enhanced significantly, which is advantageous for reduction of the air gap between the probe and the DRA antennas that influences on the samples for future application in microwave.
Rutile Dielectric Loss Dielectric Permittivity Bi2O3 Secondary Phase
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This work was partly sponsored by the U. S. Air Force Office of Scientific Research (AFOSR) (FA9550-11-1-0095), CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior). Prof. Gilberto, D. Saraiva, PhD, acknowledges the support from the MCT(Ministério da Ciência e Tecnologia)/CNPq Edital 14/2010 (process 476569/2010-9), FUNCAP (Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico)/Edital 02/2010 (process BP10031001350100/10) and FUNCAP/Edital 05/2009 (process 186.01.00/09).
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