Compacidade do suporte cerâmico cru versus propriedades do revestimento cerâmico cozido
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Data
2012-03-01
Autores
Prado, Ana Candida de Almeida
Zanardo, Antenor [UNESP]
Moreno, Maria Margarita Torres [UNESP]
Menegazzo, Paula Margarido
Título da Revista
ISSN da Revista
Título de Volume
Editor
Escola de Minas
Resumo
A compacidade é definida como a razão entre a densidade a seco e a densidade real, propriedade importante no processo cerâmico, pois, quanto maior a compacidade, menor é a necessidade de fechamento dos poros durante a sinterização. Os principais fatores que influenciam a compacidade são: distribuição granulométrica das partículas, tamanho e formato do grânulo, preenchimento do molde, pressão e umidade de prensagem. Com o objetivo de variar a compacidade de corpos de prova compostos, primordialmente, por argilas vermelhas da Formação Corumbataí da região de Rio Claro (SP - Brasil), foram aplicadas diferentes pressões durante a confecção de peças. Foram determinadas as propriedades físicas (absorção de água, retração linear, porosidades aberta, fechada e total, densidade aparente e módulo de ruptura à flexão) das referidas peças. Conclui-se que, para essas massas compostas por argilas illíticas, albita e teores relativamente elevados de hematita (± 4,5%), quanto maior é a compacidade, menor é a temperatura de queima, para se obterem produtos com um determinado padrão de absorção de água, sendo que as compacidades entre 0,66 e 0,69 apresentaram menor risco de atingir a superqueima.
Compactness is the ratio between the dry and real density of the ceramic artifact. This is an important property in the ceramic process, since the greater the compactness, the less need for pore closure in the sinter stage. The main factors that influence compactness are: particle size distribution, granule size and shape, mold filling method, humidity, and compacting pressure. The compacting pressure was modified in order to vary the compactness of the samples, which consisted primarily of red clay from the Rio Claro (SP-Brazil) region in the sedimentary deposit of the Corumbataí Formation. To understand the initial compacting influence, the physical properties of water absorption, linear shrinkage, open porosity, closed porosity, total porosity, bulk density and bending strength of the fired bodies were determined. The results indicated that, for artifacts composed of illitic clays with a relatively high content of hematite (± 4.5%), there was greater compactness at a lower firing temperature to obtain tiles with the same patterns of water absorption. However, a compactness between 0.66 and 0.69 decreased the risk of over firing occurrence, while the higher compactness tested (0.71-0.72) was excessive, increasing over firing susceptibility.
Compactness is the ratio between the dry and real density of the ceramic artifact. This is an important property in the ceramic process, since the greater the compactness, the less need for pore closure in the sinter stage. The main factors that influence compactness are: particle size distribution, granule size and shape, mold filling method, humidity, and compacting pressure. The compacting pressure was modified in order to vary the compactness of the samples, which consisted primarily of red clay from the Rio Claro (SP-Brazil) region in the sedimentary deposit of the Corumbataí Formation. To understand the initial compacting influence, the physical properties of water absorption, linear shrinkage, open porosity, closed porosity, total porosity, bulk density and bending strength of the fired bodies were determined. The results indicated that, for artifacts composed of illitic clays with a relatively high content of hematite (± 4.5%), there was greater compactness at a lower firing temperature to obtain tiles with the same patterns of water absorption. However, a compactness between 0.66 and 0.69 decreased the risk of over firing occurrence, while the higher compactness tested (0.71-0.72) was excessive, increasing over firing susceptibility.
Descrição
Palavras-chave
Compacidade, propriedades do suporte cru, propriedades do revestimento, superqueima, Compactness, properties of raw support, properties of ceramic tiles, over firing
Como citar
Rem: Revista Escola de Minas. Escola de Minas, v. 65, n. 1, p. 99-105, 2012.