In this research study, a comparative evaluation of the additional impact of nanometer-sized tetravalent oxides [Zirconia (ZrO2), Titania (TiO2), and Silica (SiO2)] on the properties and performance of Doloma-Magnesia (MgO-CaO) ceramic refractories, with an emphasis on their hydration resistance improvement, has been done. For this purpose, from 0 to 2.5wt% ZrO2, TiO2, and SiO2 nanometer-sized particles have been added to the Doloma-Magnesia compositions. After formulation and mixing of the starting materials, the pressed samples (at 150MPa) were tempered (at 250°C for 12h) and fired in a shuttle furnace (at 1650°C for 3h). The physical, mechanical, and thermo-mechanical properties of the fired samples have been investigated. Also, in order to detect the created crystalline phases and microstructure evaluation of the fired specimens, the XRD and SEM/EDS analysis have been used. The results showed that the use of silica, as well as zirconium and titanium nanometer-sized particles, have improved the sintering process via the liquid and solid state firing process mechanism, respectively. Also, the hydration resistance improvement order of the samples containing various nanometer-sized oxides is as ZrO2 > TiO2 > SiO2. Finally, in order to obtain the highest values of physical, mechanical and thermo-mechanical properties, the optimum content of each nanometer-sized tetravalent oxides was determined as ZrO2 = 2.5, TiO2 = 2.5, and SiO2 = 1wt%.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.