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Influ?ncia do teor e granulometria da calcita e da temperatura de sinteriza??o no desenvolvimento de massas cer?micas para revestimento poroso(BIII) / Influence of particle size and content of calcite and sintering temperature on the development of porous ceramic body coatingGaldino, Jos? Nildo 08 April 2010 (has links)
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Previous issue date: 2010-04-08 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work aims at studying the influence of the concentration of calcite, its grain size and
sintering temperature to obtain porous coating formulations that meet the design specifications.
The experiments involved the physical-chemical and mineralogical caracterization of the raw
materials, and mechanical tests on specimens dried and sintered, performing a planning mixture
and factorial experiment, using the response surface methodology. The ceramic bodies studied
were prepared by dry process, characterized, placed in conformity by uniaxial pressing and
sintered at temperatures of 940 ? C, 1000?C, 1060?C, 1120?C and 1180?C using a fast-firing
cycle. The crystalline phases formed during sintering at temperatures under study, revealed the
presence of anorthite and wolastonite, and quartz-phase remaining. These phases were mainly
responsible for the physical and mechanical properties of the sintered especimens. The results
shown that as increases the participation of carbonate in the composition of ceramic bodies there
is an increase of water absorption and a slight reduction in linear shrinkage for all sintering
temperatures. As for the mechanical strength it was observed that it tended to decrease for
sintering at temperatures between 940 ? C and 1060 ? C and to increase for sintering at
temperatures above 1060 ? C occurring with greater intensity for compositions with higher
content of calcite. The resistence decreased with increasing participation of quartz in all sintering
temperatures. The decrease in grain size of calcite caused a slight increase in water absorption for
formulation with the same concentration of carbonate, remaining virtually unchanged the results
of linear shrinkage and mechanical strength. In conclusion, porous ceramic coating (BIII) can be
obtained using high concentrations of calcite and keeping the properties required in technical
standards and that the particle size of calcite can be used as tuning parameter for the properties of
ceramic products. / Este trabalho objetiva estudar a influ?ncia da concentra??o de calcita, sua granulometria e
temperatura de sinteriza??o na obten??o de formula??es para revestimento poroso que atendam
as especifica??es da norma. Os experimentos envolveram a caracteriza??o f?sico qu?mica e
mineral?gica das mat?rias-primas, e ensaios mec?nicos nos corpos de prova secos e sinterizados,
precedendo-se de um planejamento de experimento de mistura e fatorial, com o uso da
metodologia de superf?cie de resposta. As massas cer?micas estudadas foram preparadas pelo
processo via seca, caracterizada, conformada por prensagem uniaxial e sinterizadas nas
temperaturas de 940?C, 1000?C, 1060?C, 1120?C, e 1180?C utilizando um ciclo de sinteriza??o
r?pido. As fases cristalina formadas durante a sinteriza??o nas temperaturas em estudo, revelaram
a presen?a de anortita e wolastonita, al?m de quartzo com fase remanescente. Estas fases foram
as principais respons?veis pelas propriedades f?sico-mec?nica dos corpos de provas sinterizados.
Verificou-se que conforme se aumenta a participa??o do carbonato na composi??o das massas
cer?micas ocorre um incremento de absor??o de ?gua e uma pequena redu??o da retra??o linear
para todas as temperaturas de sinteriza??o. J? para a resist?ncia mec?nica houve uma tend?ncia
de redu??o para sinteriza??o entre 940?C e 1060?C e aumento para sinteriza??o acima da
temperatura de 1060?C ocorrendo com maior intensidade para formula??es com maior teor de
calcita, e houve diminui??o da resist?ncia com o aumento da participa??o do quartzo em todas as
temperaturas de sinteriza??o. A diminui??o da granulometria da calcita provocou um leve
aumento na Absor??o de ?gua para formula??o com a mesma concentra??o desse carbonato
mantendo praticamente inalterados os resultados de retra??o linear e resist?ncia mec?nica.
Conclui-se que produtos cer?micos para revestimento poroso (BIII) podem ser obtidos
utilizando altas concentra??es de calcita e mantendo-se as propriedades exigidas em normas
t?cnicas e que a granulometria da calcita pode ser usada como par?metro de ajuste para as
propriedades dos produtos cer?micos
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