In-situ growth of SiOC fibers in SiOC ceramic to prepare SiOC/SiOC _f composites with polysiloxane via pre-mixing of iron chloride

A nanocomposite of silicon oxycarbide (SiOC) ceramic and silicon oxycarbide fiber was fabricated with a polysiloxane precursor by pre-mixing of iron chloride in the precursor and subsequent crosslinking, molding and pyrolysis processes. The SiOC fibers are formed in the SiOC matrix via the in-situ growth, and the pores are developed in the ceramic body in an intermediate stage of pyrolysis process. The microstructure observation reveals that the SiOC fibers are distributed in the SiOC matrix and the orientation of some fibers occurs. The interface of SiOC fibers and the ceramic matrix is formed. The energy spectral analysis indicates that the fibers have silicon, oxygen and carbon elements, showing the SiOC phase of the fiber. The composite structure of SiOC fiber/SiOC ceramic obtained with the polysiloxane by pre-mixing of iron chloride is different from that of the monolithic one formed with pure polysiloxane. The formation of SiOC fiber in the SiOC matrix is attributed to the iron catalyst introduced in the polysiloxane. The in-situ growth process can be used for the fabrication of fibers and precursor ceramic composites.