The structure of ceramic foams produced using polymeric precursors

A new method to produce silicon carbide (SiC) foams using polymeric precursor solutions was developed, where a polyurethane foam is immersed in a polymeric precursor solution to form a pre-foam which is pyrolyzed in nitrogen. The main advantages of this new approach are the simplicity and ease of control of structure of the final product. This new process is exploited further to prepare silicon carbide-silicon nitride (SiC-Si3N4) composite foams. Microstructural evidence of the improvements in structure of the ceramic foams is provided. The polysilane precursor is synthesized by the alkali dechlorination of a combination of chlorinated silane monomers in refluxing toluene/tetrahydrofuran with molten sodium as described.