نوع مقاله : مقاله کامل پژوهشی
موضوعات
عنوان مقاله English
نویسندگان English
With the growing utilization of monolithic refractories, particularly castables, considerable research efforts have been devoted to enhancing their physical, mechanical, and thermomechanical properties. To address the limitations of calcium aluminate cement associated with the formation of low-melting phases, sol–gel bonding systems have been developed as an effective strategy to improve strength and high-temperature performance. In this study, the effect of partially substituting cement with different proportions of colloidal silica in castable formulations was examined. The castables were prepared using conventional processing techniques and sintered at 1500 °C to assess their mechanical performance and microstructural characteristics. Cold crushing strength (CCS) measurements indicated that the composition containing 75% cement and 25% colloidal silica exhibited the highest CCS value of 78 MPa. Phase identification was carried out by X-ray diffraction (XRD), while field-emission scanning electron microscopy coupled with energy-dispersive spectroscopy (FESEM/EDS) revealed a notable reduction in porosity, primarily due to the lower water demand during casting. Additionally, Fourier transform infrared spectroscopy (FTIR) demonstrated the gelation process and the formation of an extensive siloxane (Si–O–Si) network. The combined formation of the calcium aluminate phase and decreased porosity contributed to the improved CCS. However, further increases in colloidal silica content led to a decline in strength, attributed to the reduced contribution of hydraulic bonding from cement.
کلیدواژهها English
