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Previous issue date: 2012-07-04 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Thin commercial aluminum electrolytic and passed through reactions was obtained with anodic alumina membranes nanopores. These materials have applications in areas recognized electronic, biomedical, chemical and biological weapons, especially in obtaining nanostructures using these membranes as a substrate or template for processing nanowires, nanodots and nanofibers for applications noble. Previous studies showed that the membranes that have undergone heat treatment temperature to 1300? C underwent changes in morphology, crystal structure and optical properties. This aim, this thesis, a study of the heat treatment of porous anodic alumina membranes, in order to obtain and to characterize the behavior changes structures during the crystallization process of the membranes, at temperatures ranging between 300 and 1700? C. It was therefore necessary to mount a system formed by a tubular furnace resistive alumina tube and controlled environment, applying flux with special blend of Ag-87% and 13% N2, in which argon had the role of carrying out the oxygen nitrogen system and induce the closing of the pores during the densification of the membrane. The duration of heat treatment ranged from 60 to 15 minutes, at temperatures from 300 to 1700? C respectively. With the heat treatment occurred: a drastic reduction of porosity, grain growth and increased translucency of the membrane. For the characterization of the membranes were analyzed properties: Physical - thermogravimetric, X-ray diffraction, BET surface area; morphological - SEM, EDS through compositional and, optical absorbance, and transmittance in the UV-VIS, and FTIR. The results using the SEM showed that crystallization has occurred, densification and significant changes in membrane structure, as well as obtaining microtube, the BET analysis showed a decrease in specific surface area of the membranes has to 44.381 m2.g-1 to less than 1.8 m2.g-1 and in the analysis of transmittance and absorbance was found a value of 16.5% in the range of 800 nm, characteristic of the near infrared and FTIR have confirmed the molecular groups of the material. Thus, one can say that the membranes were mixed characteristics and properties which qualify for use in gas filtration system, as well as applications in the range of optical wavelength of the infra-red, and as a substrate of nanomaterials. This requires the continuation and deepening of additional study / L?minas delgadas de alum?nio comercial passaram por rea??es eletrol?ticas e obtiveram-se membranas de alumina an?dica com nanoporos. Estes materiais t?m reconhecidas aplica??es nas ?reas eletr?nicas, biom?dicas, qu?micas e biol?gicas, principalmente, na obten??o de nanoestruturas utilizando estas membranas como substrato ou molde para processamento de nanofios, nanopontos e nanofibras para aplica??es nobres. Estudos anteriores apontaram que as membranas que passaram por tratamentos t?rmicos at? a temperatura de 1300? C, sofreram altera??es na morfologia, na estrutura cristalina e nas propriedades ?pticas. O objetivo deste trabalho foi o estudo do tratamento t?rmico de membranas de alumina an?dica porosas, com o intuito de obter e caracterizar as altera??es de comportamento das estruturas, durante o processo de cristaliza??o das membranas, em temperaturas que variaram entre 300 e 1700? C. Assim, foi necess?rio montar um sistema formado por um forno resistivo tubular e tubo de alumina com ambiente controlado, aplicando fluxo com mistura especial de Ar-87% e N2-13%, no qual o arg?nio teve o papel de carrear o oxig?nio para fora do sistema e o nitrog?nio de induzir o fechamento dos poros, durante a densifica??o das membranas. A dura??o dos tratamentos t?rmicos variou de 60 a 15 minutos, para as temperaturas de 300 at? 1700? C respectivamente. Com o tratamento t?rmico ocorreu redu??o dr?stica da porosidade, crescimento do gr?o e aumento da translucidez da membrana. Para a caracteriza??o das membranas, foram feitas an?lises das propriedades: f?sica - termogravim?trica; difra??o de raios-X, ?rea superficial BET; morfol?gica - MEV, composicional atrav?s do EDS; e, ?ptica - transmit?ncia e absorb?ncia no UV-VIS e FTIR. Os resultados por meio do MEV mostraram que ocorreu cristaliza??o, densifica??o e mudan?as significativas na estrutura das membranas, bem como, a obten??o de microtubo; a an?lise de BET constatou uma diminui??o na ?rea superficial espec?fica das membranas que passou de 44,381m2.g-1, para menos de 1,8m2.g-1; na an?lise de transmit?ncia e absorb?ncia foi encontrado um valor de 16,5 % na faixa de 800nm, caracter?stico do infravermelho pr?ximo e no FTIR foram confirmadas os grupos moleculares do material. Assim, pode-se afirmar que as membranas apresentaram caracter?sticas mistas e propriedades que as qualificam para o uso em sistema de filtra??o de gases, bem como, de aplica??es ?ticas na faixa do comprimento de onda do Infravermelho, e como substrato de nanomateriais. Isto requer a continuidade e aprofundamento em estudos complementares
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/12798 |
| Date | 04 July 2012 |
| Creators | Timoteo J?nior, Jos? Fl?vio |
| Contributors | CPF:06296687877, http://lattes.cnpq.br/2365059843175411, Nascimento, Rubens Maribondo do, CPF:80732810400, http://lattes.cnpq.br/8671649752936793, Silva, Gilson Garcia da, CPF:56634161453, http://lattes.cnpq.br/8681275097040450, Diniz, Marcus Alexandre, CPF:72173106449, http://lattes.cnpq.br/5997887290230186, Torquato, Wagner Lopes, CPF:03145621416, http://lattes.cnpq.br/1958198498744966, Paskocimas, Carlos Alberto |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncia e Engenharia de Materiais, UFRN, BR, Processamento de Materiais a partir do P?; Pol?meros e Comp?sitos; Processamento de Materiais a part |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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