A chemical route for the synthesis of cubic bismuth zinc niobate pyrochlore nanopowders |
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Authors: | S.M. Zanetti S.A. da Silva G.P. Thim |
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Affiliation: | Departamento de Química, Instituto Tecnológico de Aeronáutica, Centro Técnico Aeroespacial, Pça. Marechal Eduardo Gomes, 50, Vila das Acácias, 12298-900, São José dos Campos-SP, Brazil |
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Abstract: | Cubic bismuth zinc niobate pyrochlore (base composition (Bi1.5Zn0.5)(Zn0.5Nb1.5)O7) powders were successfully prepared by a chemical method. The formation mechanism of the pyrochlore phase was investigated by TG-DSC, FT-IR, Raman, and X-ray diffraction (XRD). The optical bandgap for the powders treated at temperatures ranging from 500 to 700 °C is 3.0-3.1 eV, indicating low crystallization temperature for the pyrochlore phase. No detectable intermediary phases as BiNbO4 or a pseudo-orthorhombic pyrochlore were observed at any time and the cubic-BZN phase was already formed after thermal treatment at temperatures as low as 500 °C. The phase formation study reveals that a well-crystallized single-phased nanopowder is obtained after calcination at 700 °C, indicating that the chemical synthesis conferred a higher chemical homogeneity and reactivity on the powder, modifying the crystallization mechanism. |
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Keywords: | Bi2O3-ZnO-Nb2O5 Cubic bismuth zinc niobate Pyrochlore Nanopowders Chemical method Pechini |
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