Effect of Silica Sol on Fabrication and Characterization of Silicon Carbide Ceramic Foam Filters

Ceramic foam filters (CFF) are porous ceramic pieces that have three dimensional network with open and irregular and interconnected porosities. Usually, these filters are used for refining and removal inclusions and contaminants from molten metals. In this research, silicon carbide (CFF) was made by the method immersion polyurethane sponge in ceramic slurry; different percentages of silica sol used in slurry, the influence of silica sol in properties of filters including compressive strength, and physical properties such as bulk density and porosity percent were studied. Four different temperatures were tested; 1250Ċ was a good temperature for curing. Also, the effect of silica sol in thixotropic behavior and viscosity was studied by rheometer test. Mullite and silicon carbide phases in microstructure increase compressive strength and refractoriness. Microstructure was studied by SEM. Results showed that mullite phase was made in filters.