Preparação e caracterização de pós e filmes finos cerãmicos de titanato de chumbo e estrôncio obtidos por método químico

Detalhes bibliográficos
Ano de defesa: 2006
Autor(a) principal: Leal, Sérgio Henrique Bezerra de Sousa
Orientador(a): Varela, José Arana lattes
Banca de defesa: Não Informado pela instituição
Tipo de documento: Tese
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de São Carlos
Programa de Pós-Graduação: Programa de Pós-Graduação em Química - PPGQ
Departamento: Não Informado pela instituição
País: BR
Palavras-chave em Português:
Área do conhecimento CNPq:
Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/6073
Resumo: xvii ABSTRACT In this work it is approached the preparation of ceramic powders and thin films of strontium-doped lead titanate with concentration of strontium varing from 0 to 100% mol, using a chemical method of synthesis, polymeric precursor method (Pechini). This method allows the sythesis in aqueous medium, in ambient atmosphere, using reactants easily available. In this way, the synthesis condicions were optimized in order to elimanate the formation of secondary phases. The powders ceramic treated in different temperatures under ambient atmosphere was studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), infrared spectroscopy (FTIR), micro-Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM), that allowed the identification of the crystalline phases, lattice parameters and crystallite size. A phase transition from tetragonal to cubic was observed in this system as the stontium concentration increases in the (Pb1-xSrx)TiO3. A pseudo-cubic phase was observed for x=0.5, indicanting the complete solid solubility of the system. Thin films were obtained by using spin coating of the polymeric solution on Pt/Ti/SiO2/Si substrates using a rotation speed of 7600 rpm for 30 s and calcining at 600°C for 4 h. The effect of the substituint ion in the microstructure and morphology of those films was discussed through a systematic and detailed study using XRD, FTIR, micro-Raman spectroscopy, optical microscopy and atomic force microscopy (AFM); where it was verified that addition of strontium in the PT lattice resulted in decrease of avarage grain size of those films.