Fabrication of porous SiC-based ceramic microchannels via pyrolysis of templated preceramic polymers

摘要

This article reports conversion chemistry of preceramic polymer to ceramic phase during the fabrication of high-temperature stable silicon carbide and silicon carbonitride monolithic porous microchannels. The micromolding in capillaries method is used to fabricate porous channels by the initial infiltration of a solution of 1.5-mu m diameter silica spheres or l-(mu m diameter polystyrene spheres into polydimethylsiloxane channels followed by filling the void space among the spheres by using viscous commercial polymeric precursors. Subsequently, the polymer-sphere composite channel was cured and pyrolysed at 1200 deg C under inert atmosphere, and final wet etching step of silica spheres with 10 percent hydrofluoric acid solution developed the pore structures by removing the silica spheres, whereas polystyrene sphere decomposes at the early stage of pyrolysis.