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Master's Dissertation
DOI
10.11606/D.54.1990.tde-02042015-120328
Document
Author
Full name
Eduardo Colla Ruvolo Junior
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 1990
Supervisor
Committee
Aegerter, Michel Andre (President)
Andreeta, Jose Pedro
Zanotto, Edgar Dutra
Title in Portuguese
Preparação e caracterização de sílica amorfa ultrapura pelo processo sol-gel.
Keywords in Portuguese
Não disponível
Abstract in Portuguese
A preparação de materiais vítreos e cerâmicos pelo processo sol-gel vem ganhando um desenvolvimento muito grande nos últimos anos, superando em muitos casos as tecnologias convencionais. Este trabalho apresenta um processo sol-gel original de modo a obter sílica densa, amorfa e monolítica cuja estrutura gel é reforçada mecanicamente pela adição ao sol inicial de microesferas de sílica preparadas pelo método de Stöber ou pó de sílica comercial (Cab-O-Sil M5), evitando o problema de quebras. Análises feitas com microscopia eletrônica de transmissão (TEM), área superficial BET, tempo de gelificação, difratometria de raio-x, densidade, microdureza Vickers, espectroscopia de absorção óptica do ultravioleta ao infravermelho caracterizam cada uma das etapas das transições sol-gel úmido-gel seco-vidro. Os materiais vítreos preparados apresentam qualidade óptica comparável à da sílica comercial
Title in English
Not available
Keywords in English
Not available
Abstract in English
The preparation of glasses and ceramics by the sol-gel process received notable development in the last few years, showing in many cases great advantages on conventional technologies. This work presents an original sol-gel process in order to obtain dense, amorphous and monolithic-silica whose gel structure is reinforced mechanically by addition to the initial sol of either silica microspheres prepared by the Stöber method or fumed silica powder (Cab-O-Sil M5 Cabot), avoiding the cracks problem. Analysis of transmission electron microscopy (TEM), BET surface area, gelation time, x-ray difratometry, density, Vickers microhardness, optical spectroscopy absorption from UV to IR were used to characterize each step of the process sol-wet, gel-dry gel-glass. SiO2 glasses materials prepared in this way present optical quality similar to that obtain commercially
 
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Publishing Date
2015-04-07
 
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