Ozone infusiblization and curing mechanism of polysilazane ceramic precursor fibers

An appropriate infusible method plays a vital role as one of the key processes of the fabrication of polymer-derived ceramic fibers. In this work, ozone curing, a novel room temperature controllable curing strategy was used to prepare SiCN ceramic fibers. Some circular pores were observed on the surface of the obtained SiCN ceramic fibers. The tensile strength of the fibers was also investigated. To reveal the ozone-curing mechanisms of the PSZ fibers and the formation process of the circular pores, the FT-IR, SEM, OM, XRD and TG were characterized. The results showed that the Si–H bonds and Si-CH 3 groups in the PSZ molecule were oxidized gradually to form oxygen-containing groups such as Si–OH, Si–O-Si and C = O in the ozone curing process, which contributed to the curing and weight gain of the PSZ fibers. Moreover, a hydrolysis reaction between Si-NH-Si and H 2 O might further accelerate the curing of the PSZ fibers. An unexpected result of the hydrolysis reaction is the formation of some circular pores on the surface layer of the PSZ fibers. This strategy provides a method to design, adjust and control the microstructure and composition of silicon-based ceramic fibers, and the obtained SiCN fibers may be used as catalyst support, bacterial culture and other fields.