Fabrication of low-cost SiC foams from sugar and recycled polymeric templates

Macroporous ceramic foams are used in different fields due to their unique properties, which include: low density, low thermal conductivity, high permeability, high temperature stability and high resistance to chemical attack. Highly porous silicon carbide (SiC) foams are materials of great interest for absorption, catalytic support, and thermal insulation applications, among others, due to their chemical resistance, large surface area, low flow resistance, low pressure drop, as well as high resistance to temperature and corrosion. In this work, highly porous, SiC foams were fabricated via template replica, using recycled polymeric foams as sacrificial templates. A sucrose-based resin containing silica powder was used as a foam precursor. Polymeric templates were impregnated, followed by thermal treatment at 1500 °C under inert atmosphere. The effect of C/SiO2 mass ratio (1.0-1.75) in the precursor and the use of alumina (0.5 - 2.5 %wt/v) as a sintering additive were evaluated in terms of the morphology of the fabricated foams, as well as SiC yield.