Deformação piroplástica em porcelanatos
Fecha
2016-09-09Autor
Conserva, Lisandra Rafaela dos Santos
Metadatos
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In recent years porcelain stoneware tiles showed the highest growth in
production and consumption in ceramic industry sector. To achieve low
porosity, which ensures the high performance of the product, is required the
formation of large amount of liquid phases during sintering and the flow of these
liquids are responsible for the undesirable pyroplastic deformation. Some
factors exacerbate the problem: large and rectangular shapes and faster firing
cycles. Moreover, the production of tiles through a more sustainable route, the
dry route, lacks studies evaluating the effects of processing method on
pyroplastic deformation. Thus, this study aimed to contribute to reducing the
incidence of pyroplastic deformations in porcelain stoneware tiles, in order to
identify the main variables involved and suggest maneuvers for achieve this
goal. In the first stage, technical porcelain stonewares were formulated using
common raw materials in this type of manufacturing and prepared by wet route.
The main difference between the batches was that 10% of the feldspar was
replaced with other raw materials such as potash feldspar and quartz in
different granulometries in order to change the characteristics of the liquid
phases and to minimize pyroplastic deformation. The characterization of the
batches before and after firing, as well the assessment of physical and chemical
/ mineralogical effects of the raw materials on deformation behavior was
essential to identify the variables prevalent in deformation. In second stage
some batches from previous step were prepared by dry route method, and then
the same tests were performed in order to evaluate the effects of processing
route on pyroplastic deformation. The results indicated that batches prepared by
dry processing route are less likely to deformation mainly due to heterogeneity
of microstructure. In both stages, it was found out that the viscosity of the liquid
phase formed during firing is the variable that affects most significantly the
pyroplastic deformation of the porcelain obtained by both processing routes
studied.