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@MastersThesis{Alves:2017:EsObCa,
               author = "Alves, Adriano Cavalca",
                title = "Estudo da obten{\c{c}}{\~a}o e caracteriza{\c{c}}{\~a}o de 
                         aluminas alfa nanoparticuladas via s{\'{\i}}ntese 
                         qu{\'{\i}}mica e tratamento t{\'e}rmico convencional",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2017",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "2017-05-29",
             keywords = "nanoparticulado, aluminas de transi{\c{c}}{\~a}o, alumina alfa, 
                         aglomerados, s{\'{\i}}ntese sol-gel, nanoparticulate, transition 
                         aluminas, alumina alfa, clusters, sol-gel synthesis.",
             abstract = "O objetivo principal deste trabalho foi estudar e determinar os 
                         par{\^a}metros de processamento e procedimentos para 
                         obten{\c{c}}{\~a}o de p{\'o}s nanoparticulados de aluminas de 
                         transi{\c{c}}{\~a}o e alumina est{\'a}vel (\$\alpha\$). 
                         Estes materiais foram obtidos via s{\'{\i}}ntese sol-gel, por 
                         precipita{\c{c}}{\~a}o a partir de solu{\c{c}}{\~a}o aquosa de 
                         nitrato de alum{\'{\i}}nio 
                         [Al(NO\$_{3}\$)\$_{3}\$.9H\$_{2}\$O] com hidr{\'o}xido de 
                         am{\^o}nio (NH\$_{4}\$OH), obtendo alumina hidratada, e 
                         subsequentes tratamentos t{\'e}rmicos at{\'e} 1200\$^{o}\$C. 
                         Para estudo da forma{\c{c}}{\~a}o de aglomerados e agregados das 
                         part{\'{\i}}culas precipitadas, estas foram solvatadas com 
                         subst{\^a}ncias qu{\'{\i}}micas com tamanhos de mol{\'e}culas 
                         e polaridades diferentes: {\'a}gua, {\'a}lcool et{\'{\i}}lico 
                         e {\'a}cido ac{\'e}tico. As obten{\c{c}}{\~o}es das aluminas 
                         de transi{\c{c}}{\~a}o e est{\'a}vel (\$\alpha\$) foram 
                         feitas utilizando tratamentos t{\'e}rmicos em forno convencional. 
                         Na etapa de solvata{\c{c}}{\~a}o das part{\'{\i}}culas das 
                         aluminas hidratadas precipitadas estudou-se o efeito da secagem 
                         est{\'a}tica (na temperatura ambiente) no estado de 
                         aglomera{\c{c}}{\~a}o/agrega{\c{c}}{\~a}o destas 
                         part{\'{\i}}culas dos p{\'o}s. De forma comparativa estudou-se 
                         as caracter{\'{\i}}sticas morfol{\'o}gicas dos p{\'o}s de 
                         alumina obtidos em diferentes calcina{\c{c}}{\~o}es em forno 
                         convencional em rela{\c{c}}{\~a}o {\`a} forma{\c{c}}{\~a}o de 
                         aglomerados e agregados em fun{\c{c}}{\~a}o da temperatura e 
                         tempo no tratamento t{\'e}rmico. Os p{\'o}s foram caracterizados 
                         quanto {\`a} morfologia, forma e estado de 
                         aglomera{\c{c}}{\~a}o/agrega{\c{c}}{\~a}o por FEG-MEV 
                         (microsc{\'o}pio eletr{\^o}nico de varredura de alta 
                         resolu{\c{c}}{\~a}o), identifica{\c{c}}{\~a}o das fases 
                         cristalinas por difratometria de raios X (DRX) e 
                         determina{\c{c}}{\~a}o da {\'a}rea espec{\'{\i}}fica pelo 
                         m{\'e}todo BET (Brunauer Emmett Telller). De acordo com os 
                         resultados de caracteriza{\c{c}}{\~a}o as aluminas tratadas 
                         at{\'e} 1100\$^{}\$C s{\~a}o compostas por 
                         nanopart{\'{\i}}culas aglomeradas, e partir de 1200\$^{}\$C 
                         por part{\'{\i}}culas submicrom{\'e}trica. A alumina hidratada 
                         e solvatada, com solu{\c{c}}{\~a}o aquosa de {\'a}cido 
                         ac{\'e}tico a 40 \%, al{\'e}m de ser nanoparticulada, 
                         apresentou a menor temperatura de forma{\c{c}}{\~a}o de fase 
                         cristalina est{\'a}vel (fase \$alpha\$) ap{\'o}s 
                         calcina{\c{c}}{\~a}o em 1100 \$^{}\$C. ABSTRACT: The main 
                         objective of this work was to study and determine the processing 
                         parameters and procedures for obtaining nanoparticulate powders of 
                         transition aluminas and stable alumina (\$\alpha\$). These 
                         materials were obtained by sol-gel synthesis by precipitation from 
                         aqueous solution of aluminum nitrate [Al (NO3) 3.9H2O] with 
                         ammonium hydroxide (NH\$_{4}\$OH), obtaining hydrated alumina, 
                         and subsequent thermal treatments up to 1200\$^{}\$C. To study 
                         the formation of clusters and clusters of precipitated particles, 
                         they were solvated with chemicals of different molecule sizes and 
                         polarities: water, ethyl alcohol and acetic acid. The transition 
                         and stable alumina (\$\alpha\$) were obtained using 
                         conventional furnace heat treatments. In the solvation step of the 
                         precipitated hydrated alumina particles, the effect of static 
                         drying (at room temperature) on the agglomeration / aggregation 
                         state of these powders particles was studied. In a comparative 
                         way, the morphological characteristics of the alumina powders 
                         obtained in different conventional kiln calcination were studied 
                         in relation to the formation of agglomerates and aggregates as a 
                         function of temperature and time in the heat treatment. The 
                         powders were characterized in terms of morphology, shape and state 
                         of agglomeration / aggregation by FEG-MEV (high resolution 
                         scanning electron microscope), identification of crystalline 
                         phases by X-ray diffractometry (XRD) and determination of the 
                         specific area by BET method Brunauer Emmett Telller). According to 
                         the characterization results the aluminas treated up to 1100 
                         \$^{}\$ C are composed of agglomerated nanoparticles, and from 
                         1200 \$^{}\$ C by submicron particles. The alumina hydateded 
                         obtained from solvatation with acetic acid and calcined at 1100 
                         \$^{o}\$C, resulted in nanoparticles agglomerates and 
                         \$\alpha\$ alumina.",
            committee = "Nono, Maria do Carmo de Andrade (presidente/orientadora) and 
                         Mineiro, Sergio Luiz (orientador) and Machado, Jo{\~a}o Paulo 
                         Barros and Assis, Jo{\~a}o Marcos Kruszynski de",
         englishtitle = "Study of the obtaination and characterization of 
                         \α-nanoparticulated alumines via chemical synthesis and 
                         conventional thermal treatment",
             language = "pt",
                pages = "81",
                  ibi = "8JMKD3MGP3W34P/3NTHB8L",
                  url = "http://urlib.net/rep/8JMKD3MGP3W34P/3NTHB8L",
           targetfile = "publicacao.pdf",
        urlaccessdate = "29 nov. 2020"
}


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