A method for the production of porous SiC-ceramics from finely dispersed starting system SiO2–C by means of single-stage carbothermal process involving spark plasma sintering at moderate temperatures (≤1800 °C) is proposed. Synthesis of finely-dispersed SiO2–C system was performed by sol–gel as follows: tetraethoxysilane was hydrolyzed in the presence of polymeric source of carbon (phenolformaldehyde resin) with the subsequent drying and thermal treatment under inert atmosphere at 850 °C. The density of the obtained ceramic samples was found to vary within the range 1.43–1.84 g·cm−3 depending on the experimental conditions (the estimated porosity amounted to 42–55%). Ultimate compression strength was measured to be 94–279 MPa. Thermal behavior of materials in air flow up to 1400 °C, as well as microstructure and volumetric pore distribution (X-ray computerized microtomography), were studied.
Graphical Abstract