ESTUDO DE FASES E CRESCIMENTO DE MONOCRISTAIS NO SISTEMA Bi2O3 - TiO2 - ZrO2
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Data
2008-08-18
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Universidade Federal de Goiás
Resumo
I
n this work a systematic study on the phase formation and stability in the
system Bi2O3-ZrO2 was realized, the solubility of the Zr4+ ion in Bi12TiO20
(BTO) was investigated and Zr-doped BTO crystals (BTO:Zr) were grown
and optically characterized. It was verified that a tetragonal phase was
formed in the following wide composition interval: (6-x)Bi2O3:(1+x)ZrO2, with
x = 0.5, 0.3, 0.2, 0.1, 0, -0.1, -0.2, -0.3, -0.5, -0.65 e -0.7. The phases were
synthesized by solid state reaction and the powders were characterized by Xray
diffraction and diferential thermal analysis. The formed tetragonal phase,
however, was metastable for all investigated compositions and its
preparation was dependent on the sample thermal history. The stable phase
at room temperature was a monoclinic one. A low solubility of Zr4+ in BTO
was verified, but BTO:Zr single crystals were grown by Top Seeded Solution
Growth (TSSG) technique. Good quality crystalline samples were prepared
and characterized by chemical compositon and by optical activity,
photoconductivity and electro-optical measurements. The results shown that
Zr-doping produced a decreasing in the crystal photosensitivity, and almost
no changes in the optical activity and electro-optical coefficient were
generated.
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Citação
FERREIRA, Katiúscia Daiane. Crystal growth; Photorefractive crystals; solid state synthesis; Bi2O3 - TiO2 - ZrO2. 2008. 67 f. Dissertação (Mestrado em Educação em Química) - Universidade Federal de Goiás, Goiânia, 2008.