CONICET | Buscador de Institutos y Recursos Humanos

Main problems in the reaction-sintering process to produce zirconia toughened mullite ceramics are related with composite microstructure including the grain size control of zirconia inclusions, relative proportion of t-ZrO2 and the presence of secondary phases. These factors determine the final properties of the mullite based composite and its possible industrial application. In this work, Mullite-ZrO2 composites were produced from stoichiometric mixtures of alumina and zircon (molar ratio 3:2) by slip casting and reaction sintering employing cerium oxide as additive (5 to 15 % mol in ZrO2). The effect of different ceria content in the starting powder composition and sintering temperature (1400 and 1600ºC-2h) on the densification and conversion as well as the resultant microstructure of composites was examined using the XRD and SEM-EDAX techniques. Crystalline phase development on sintering was quantitatively determined by XRD using the Rietveld method. These measurements allowed the calculation of the conversion of the corresponding reaction products (zirconia and mullite) for different sintering temperatures. Formation of mullite, which occurred at a relatively low temperature, took place in a presence of a liquid phase instead of the usual solid state process.2 and the presence of secondary phases. These factors determine the final properties of the mullite based composite and its possible industrial application. In this work, Mullite-ZrO2 composites were produced from stoichiometric mixtures of alumina and zircon (molar ratio 3:2) by slip casting and reaction sintering employing cerium oxide as additive (5 to 15 % mol in ZrO2). The effect of different ceria content in the starting powder composition and sintering temperature (1400 and 1600ºC-2h) on the densification and conversion as well as the resultant microstructure of composites was examined using the XRD and SEM-EDAX techniques. Crystalline phase development on sintering was quantitatively determined by XRD using the Rietveld method. These measurements allowed the calculation of the conversion of the corresponding reaction products (zirconia and mullite) for different sintering temperatures. Formation of mullite, which occurred at a relatively low temperature, took place in a presence of a liquid phase instead of the usual solid state process.2 composites were produced from stoichiometric mixtures of alumina and zircon (molar ratio 3:2) by slip casting and reaction sintering employing cerium oxide as additive (5 to 15 % mol in ZrO2). The effect of different ceria content in the starting powder composition and sintering temperature (1400 and 1600ºC-2h) on the densification and conversion as well as the resultant microstructure of composites was examined using the XRD and SEM-EDAX techniques. Crystalline phase development on sintering was quantitatively determined by XRD using the Rietveld method. These measurements allowed the calculation of the conversion of the corresponding reaction products (zirconia and mullite) for different sintering temperatures. Formation of mullite, which occurred at a relatively low temperature, took place in a presence of a liquid phase instead of the usual solid state process.2). The effect of different ceria content in the starting powder composition and sintering temperature (1400 and 1600ºC-2h) on the densification and conversion as well as the resultant microstructure of composites was examined using the XRD and SEM-EDAX techniques. Crystalline phase development on sintering was quantitatively determined by XRD using the Rietveld method. These measurements allowed the calculation of the conversion of the corresponding reaction products (zirconia and mullite) for different sintering temperatures. Formation of mullite, which occurred at a relatively low temperature, took place in a presence of a liquid phase instead of the usual solid state process.