Résumé
Recently, silicon carbide (SiC) attracted interest for environmentaland energy applications according to its mechanical and chemicalproperties at high temperature. Yet, most of the actual andfuture industrial challenges of silicon-based ceramics require materialswith compositions, shapes and textures tuned on demand.Common techniques are energy-ineffective and limit the shape andtexture complexities of the parts made. Moreover, the control of theproduct purity and crystalline form is restricted. These difficultiescan be overcome by synthetic paths where molecular chemistry andchemistry of materials are combined rationally, like the Polymer-Derived Ceramics (PDCs) route. This process is applied here tomake boron-modified SiC foams. The polymer was synthesizedby reaction of allylhydridopolycarbosilane (AHPCS) with boranedimethyl sulfide to get highly crosslinked polymers. The polymersare fully characterized by infrared and solid state NMR. By mixingthe polymer with PMMA spheres, then applying a warm-pressing,hybrid pellets are made. A pyrolysis up to 1000°C under argonallowed converting the inorganic part into SiC and removing theorganic part leaving voids in the pellets. This produced microcellularfoams are characterized by mercury porosimetry and SEM.The structural evolution of the amorphous SiC has been followed byXRD and Raman spectrometry. Application will be briefly described.