Fabrication of SiC-based ceramic microstructures from preceramic polymers with sacrificial templates and lithographic techniques - A review

Processes for fabricating ceramic microstructures are in demand for use in areas such as microreactors and MEMS that can be used in harsh environments requiring a high temperatures tolerance, corrosion resistance, as well as tribological properties. This review describes the manufacture of tailored porous SiC ceramic microstructures using sacrificial templates, the feasible applications of microporous structures and microchannels as a microreactor, and microfabrication of preceramic polymers using soft lithography and sterolithography. Macroporous and mesoporous SiC ceramic structures have been fabricated using various templates including packed silica sphere assemblies, porous carbon templates, and nanoporous silica structures. In addition, SiC nanotubes have also been obtained from an alumina membrane used as a template. These porous structures were generally obtained using a series of infiltration, curing and pyrolysis, and chemical or oxidative etching steps. Complicated SiC ceramic microfeatures were fabricated using near-net shape lithographic techniques to preceramic polymers. Line patterns and porous channels were produced by soft lithography, whereas the 3D woodpile structures were fabricated using stereolithography. These novel structures show great promises for use in high temperature micro-reactors for the on-demand reforming of higher hydrocarbons into hydrogen in portable power sources. It is expected that the integration of preceramic polymers into new economic manufacturing strategies such as precursor casting in templates and lithography utilization will be a break-through technology for the creation of complex ceramic nanostructures.