@MastersThesis{Martins:2024:EsCoCe,
               author = "Martins, Arthur Ferreira",
                title = "Estudo de comp{\'o}sitos cer{\^a}micos de alumina com carbeto de 
                         sil{\'{\i}}cio e zirc{\^o}nia para aplica{\c{c}}{\~a}o 
                         espacial via manufatura aditiva",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2024",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "2023-09-13",
             keywords = "robocasting, manufatura aditiva, alumina, 
                         sinteriza{\c{c}}{\~a}o, resist{\^e}ncia {\`a} flex{\~a}o, 
                         robocasting, additive manufacturing, alumina, sintering, flexural 
                         strength.",
             abstract = "Neste estudo, foi empregado a t{\'e}cnica de Robocasting para 
                         imprimir amostras destinadas {\`a} caracteriza{\c{c}}{\~a}o de 
                         propriedades f{\'{\i}}sicas e mec{\^a}nicas. Os ensaios 
                         conduzidos abordaram resist{\^e}ncia {\`a} flex{\~a}o, 
                         difratometria, microscopia, picnometria, densidade via m{\'e}todo 
                         de Arquimedes, {\'a}rea superficial e retra{\c{c}}{\~a}o 
                         linear. Tr{\^e}s composi{\c{c}}{\~o}es distintas foram 
                         preparadas: alumina {{pura;}} alumina com adi{\c{c}}{\~a}o de 4% 
                         de carbeto de sil{\'{\i}}cio e 7,5% de {{zirc{\^o}nia;}} e 
                         alumina com 10% de zirc{\^o}nia. As formula{\c{c}}{\~o}es 
                         atingiram, 70-74% de material cer{\^a}mico em p{\'o}, 26-22% de 
                         {\'a}gua, 3,5% de PEG e 0,5% de CMC. Foi identificado que a 
                         velocidade de impress{\~a}o exerce influ{\^e}ncia direta sobre a 
                         precis{\~a}o dimensional. Ajustes no fluxo e altura de camada 
                         s{\~a}o cr{\'{\i}}ticos para a correta dimens{\~a}o da 
                         amostra. Observou-se que a impressora possui um erro 
                         intr{\'{\i}}nseco, impedindo a reprodu{\c{c}}{\~a}o exata das 
                         dimens{\~o}es entre m{\'u}ltiplas pe{\c{c}}as. Bicos de 
                         impress{\~a}o menores tendem a entupir e operar em baixa 
                         velocidade, mas proporcionam maior precis{\~a}o. As amostras 
                         foram submetidas {\`a} sinteriza{\c{c}}{\~a}o em 1600 °C 
                         durante 180 minutos, com fases intermedi{\'a}rias para 
                         volatiza{\c{c}}{\~a}o dos aditivos PEG e CMC. As densidades 
                         relativas das amostras situaram-se entre 60 e 70%. As 
                         microestruturas apresentaram porosidade residual e uniforme 
                         confirmada pela an{\'a}lise de microscopia eletr{\^o}nica. A 
                         adsor{\c{c}}{\~a}o de N2 indicou a aus{\^e}ncia de micro ou 
                         mesoporos. Notavelmente, em amostras contendo carbeto de 
                         sil{\'{\i}}cio, houve a apari{\c{c}}{\~a}o de uma nova fase, 
                         denominada mulita (Al6Si2O13) devido {\`a} 
                         sinteriza{\c{c}}{\~a}o em ambiente n{\~a}o controlado. Os 
                         resultados de resist{\^e}ncia {\`a} flex{\~a}o apresentaram 
                         valores baixos em consequ{\^e}ncia da baixa densidade das 
                         cer{\^a}micas, variando entre 20 MPa e 67 MPa, com uma 
                         significativa melhora quando modificado o preparo das massas 
                         cer{\^a}micas pesquisadas. ABSTRACT: In this study, the technique 
                         of Robocasting was employed to print parts intended for the 
                         characterization of physical and mechanical properties. The tests 
                         conducted addressed flexural strength, diphratometry, microscopy, 
                         picnometry, density via the Archimedes method, surface area, and 
                         linear retraction. Three distinct compositions were prepared: pure 
                         {{alumina;}} alumina with the addition of 4% silicon carbide and 
                         7.5% {{zirconia;}} and alumina with 10% zirconia. The formulations 
                         reached 70-74% powdered ceramic material, 26-22% water, 3.5% PEG 
                         and 0.5% CMC. It has been identified that printing speed has a 
                         direct influence on dimensional accuracy. Adjustments in the flow 
                         and layer height are critical for the correct sample size. It was 
                         noted that the printer has an intrinsic error, preventing the 
                         exact reproduction of dimensions between multiple pieces. Smaller 
                         print nozzles tend to clog and operate at low speeds, but they 
                         provide greater accuracy. The parts were sintered at 1600 °C for 
                         180 minutes, with intermediate phases for volatization of PEG and 
                         CMC additives. The relative densities of the samples were between 
                         60 and 70%.Microscopic analysis confirmed that the microstructures 
                         had residual and uniform porosity. N2 adsorption indicated the 
                         absence of micro or mesopores. Notably, in parts containing 
                         silicon carbide, there was the appearance of a new phase called 
                         mullite (Al6Si2O13) due to sintering in an uncontrolled 
                         environment. The results of flexural strength showed low values 
                         due to the low density of ceramics, ranging between 20 MPa and 67 
                         MPa, with a significant improvement when the preparation of the 
                         ceramic masses studied was modified.",
            committee = "Okamoto, Sayuri (presidente/orientador) and Oliveira, Isaias de 
                         (orientador) and Mineiro, Sergio Luiz (orientador) and Dyer, 
                         Silvelene Alessandra Silva and Assis, Jo{\~a}o Marcos Kruszynski 
                         de",
         englishtitle = "A study of ceramic composites of alumina with silicon carbide and 
                         zirconia for space application by additive manufacturing",
             language = "pt",
                pages = "108",
                  ibi = "8JMKD3MGP3W34T/49S7A5P",
                  url = "http://urlib.net/ibi/8JMKD3MGP3W34T/49S7A5P",
           targetfile = "publicacao.pdf",
        urlaccessdate = "05 maio 2024"
}