Novo sistema vítreo zinco-boro telureto: síntese, caracterização e potencial de aplicações
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Data
2017-08-28
Autores
Lunas, Fabrícia Roberta
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Universidade Estadual Paulista (Unesp)
Resumo
O novo sistema vítreo ZBT, 70 ZnO-30B2O3 (mol%) + xTe (wt%), sendo (x= 0, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50) foi sintetizado por meio da técnica fusão resfriamento. As amostras foram tratadas termicamente numa temperatura de 450°C por um período de 3 h. Foi feito o estudo estrutural, térmico e óptico do sistema vítreo a partir das técnicas de Difratometria de Raios-X, Espectroscopias FT-IR e Raman, Análise Térmica Diferencial, Absorção óptica; Índice de refração e Determinação da densidade. O trabalho em questão tem como objetivo sintetizar uma matriz vítrea hospedeira que apresente boas características estruturais, térmicas e ópticas com potencial para aplicações tecnológicas. O índice de refração das amostras vítreas ZBT varia de acordo com a composição do material, a concentração com 0 Te (%wt) apresentou índice de refração de 1,48, enquanto que para concentração 50 Te Te (%wt) o índice de refração é de 1,84. Este aumento no índice de refração potencializa o material vítreo para aplicações ópticas. Tratamentos térmicos acima da Tg foram feitos a fim de estudar o comportamento térmico, em termos de estabilidade térmica e cristalização do vidro. Os vidros apresentaram boa estabilidade térmica, podendo ser aplicados em fibras ópticas. Espectroscopia Raman identificaram ligações O-Te-O; tetraedros ZnO; presença de anéis de boroxol com triângulos BO3 e tetraedros BO4, ligações Te-O- e vibrações de estiramento Te=O em TeO3+1 que indicam presença de oxigênios não ligantes (non-bridging NBO’s). Espectros de FT-IR revelam bandas correspondentes a ZnO, TeO3, TeO6, BO3, BO4. Os espectros de absorção do sistema vítreo zinco-boro teluretos indicam que as amostras são transparentes nas faixas do visível ao infravermelho próximo. Os difratrogramas de Raios-X informaram que nem todas as composições possuem estrutura amorfa. Na referida temperatura de tratamento térmico de 450°C por um tempo de 3h, as amostras com concentrações 10, 20 e 30 Te (wt%) apresentaram a fase cristalina ZnB4O7, caracterizando estas composições como vitrocerâmicas. A partir dos estudos analisados foi possível obter informações a respeito das propriedades do vidro, e suas características para potenciais aplicações.
The new glassy system ZBT, 70 ZnO-30B2O3 (mol%) + xTe (wt%), being (x = 0, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50) was synthesized by melting quentching. The samples were thermally treated at temperature of 450° C for 3 h. Structural, thermal and optical analysis of the vitreous system were carried out by of X-ray Diffraction, FT-IR and Raman Spectroscopy, Differential Thermal Analysis, Optical Absorption, Index of refraction and Determination of density techniques. The work in question aims to synthesize a host glass matrix that presents good structural, thermal and optical characteristics with potential technological applications. The refractive index of the ZBT glass samples varies according to the composition of the material, the concentration with 0 Te (% wt) had a refractive index of 1.48, whereas for the concentration 50 Te Te (% wt) the refractive index is 1.84. This increase in the refractive index enhances the vitreous material for optical applications. Thermal treatments above the Tg were done in order to study the thermal behavior in terms of thermal stability and glass crystallization. The glasses presented good thermal stability and could be applied in optical fibers. Raman spectroscopy has identified O-Te-O bonds; ZnO tetrahedra; presence of boroxol rings with BO3 triangles and BO4 tetrahedra, Te-O- bonds and Te=O stretching vibrations in TeO3+1 indicating the presence of non-bridging NBO's. FT-IR spectra reveal bands corresponding to ZnO, TeO3, TeO6, BO3, BO4. The absorption spectra of the vitreous-boron-boron telluride system indicate that the samples are transparent in the bands of visible to near infrared. X-ray diffractograms reported that not all compositions have amorphous structure. At the referred temperature of 450°C for a time of 3h, samples with concentrations 10, 20 and 30 Te (wt%) presented the crystalline phase ZnB4O7, characterizing these compositions as glass-ceramic. From the analyzed studies it was possible to obtain information about the properties of the glass, and its characteristics for potential applications.
The new glassy system ZBT, 70 ZnO-30B2O3 (mol%) + xTe (wt%), being (x = 0, 1, 2, 3, 4, 5, 10, 20, 30, 40, 50) was synthesized by melting quentching. The samples were thermally treated at temperature of 450° C for 3 h. Structural, thermal and optical analysis of the vitreous system were carried out by of X-ray Diffraction, FT-IR and Raman Spectroscopy, Differential Thermal Analysis, Optical Absorption, Index of refraction and Determination of density techniques. The work in question aims to synthesize a host glass matrix that presents good structural, thermal and optical characteristics with potential technological applications. The refractive index of the ZBT glass samples varies according to the composition of the material, the concentration with 0 Te (% wt) had a refractive index of 1.48, whereas for the concentration 50 Te Te (% wt) the refractive index is 1.84. This increase in the refractive index enhances the vitreous material for optical applications. Thermal treatments above the Tg were done in order to study the thermal behavior in terms of thermal stability and glass crystallization. The glasses presented good thermal stability and could be applied in optical fibers. Raman spectroscopy has identified O-Te-O bonds; ZnO tetrahedra; presence of boroxol rings with BO3 triangles and BO4 tetrahedra, Te-O- bonds and Te=O stretching vibrations in TeO3+1 indicating the presence of non-bridging NBO's. FT-IR spectra reveal bands corresponding to ZnO, TeO3, TeO6, BO3, BO4. The absorption spectra of the vitreous-boron-boron telluride system indicate that the samples are transparent in the bands of visible to near infrared. X-ray diffractograms reported that not all compositions have amorphous structure. At the referred temperature of 450°C for a time of 3h, samples with concentrations 10, 20 and 30 Te (wt%) presented the crystalline phase ZnB4O7, characterizing these compositions as glass-ceramic. From the analyzed studies it was possible to obtain information about the properties of the glass, and its characteristics for potential applications.
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Palavras-chave
Vidros zinco-boro teluretos, Vitrocerâmicas, Aplicações tecnológicas, Zinc-Boron glasses, Vitroceramics, Technological applications