China whiteware products represent a large part of ceramic materials and cover a wide range of applications like tile, dinnerware and sanitary-ware. They are mainly formed by a vitreous body which comes from heating above 1100 °C a mixture of clays, fluxing agents (typically feldspar) and fillers (typically quartz), after previous processing like, for example, aging, drying and body preparation [1](Carty and Senapati, 1998). Phase composition of vitreous body has been widely studied in past and is characterized by a glassy matrix with some crystalline phases like mullite, which forms upon heating, and residual filler [2](Martin-Marquez et al., 2009). Additionally, a well developed porosity can be present, with consequent implication on some technological properties of the materials like mechanical strength [3](Braganca and Bergman, 2003). Four different industrial sanitary-ware compositions were prepared by fixing the "hard" compound (21 % feldspar, 19 % quartz and 6 % China whiteware waste) and by varying the "plastic" compound with four different industrial clay components (one per sample). After casting procedure, half of each sample was saved to investigate the packing of the green body whilst the other half was fired in a muffle furnace at the peak temperature of 1200 °C to investigate the final mineralogy and microstructure of the fired product, for a total of eight samples. All these eight samples, after previous XRPD characterization, have been investigated by Synchrotron Computed Microtomography at the SYRMEP beamline (Elettra, Trieste) in phase contrast modality and by Synchrotron Diffraction Tomography. Data reconstructions have been performed and the microstructure and mineralogy have been evaluated by processing slices with a Matlab written code. In particular, it was possible to focus on the 3D porosity (pore size distribution, pore orientation and their connectivity, etc). These results were then compared with mercury porosimeter measurements. Finally the 3D phase distribution within the fired bodies was performed by means fo Diffarction Tomography. All these observations appear fundamental for assesing the role of the plastic component of the raw materials on the final mineralogy and microstructure of the fired ceramic bodies.
Influence of raw materials on the mineralogy and microstructure of fired sanitary-ware vitreous body by synchrotron X-Ray Computed Microtomography and Diffraction Tomography
Marinoni N;Diella V;
2019
Abstract
China whiteware products represent a large part of ceramic materials and cover a wide range of applications like tile, dinnerware and sanitary-ware. They are mainly formed by a vitreous body which comes from heating above 1100 °C a mixture of clays, fluxing agents (typically feldspar) and fillers (typically quartz), after previous processing like, for example, aging, drying and body preparation [1](Carty and Senapati, 1998). Phase composition of vitreous body has been widely studied in past and is characterized by a glassy matrix with some crystalline phases like mullite, which forms upon heating, and residual filler [2](Martin-Marquez et al., 2009). Additionally, a well developed porosity can be present, with consequent implication on some technological properties of the materials like mechanical strength [3](Braganca and Bergman, 2003). Four different industrial sanitary-ware compositions were prepared by fixing the "hard" compound (21 % feldspar, 19 % quartz and 6 % China whiteware waste) and by varying the "plastic" compound with four different industrial clay components (one per sample). After casting procedure, half of each sample was saved to investigate the packing of the green body whilst the other half was fired in a muffle furnace at the peak temperature of 1200 °C to investigate the final mineralogy and microstructure of the fired product, for a total of eight samples. All these eight samples, after previous XRPD characterization, have been investigated by Synchrotron Computed Microtomography at the SYRMEP beamline (Elettra, Trieste) in phase contrast modality and by Synchrotron Diffraction Tomography. Data reconstructions have been performed and the microstructure and mineralogy have been evaluated by processing slices with a Matlab written code. In particular, it was possible to focus on the 3D porosity (pore size distribution, pore orientation and their connectivity, etc). These results were then compared with mercury porosimeter measurements. Finally the 3D phase distribution within the fired bodies was performed by means fo Diffarction Tomography. All these observations appear fundamental for assesing the role of the plastic component of the raw materials on the final mineralogy and microstructure of the fired ceramic bodies.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
