SiC nanograins stabilized Si-C-B-N fibers with ultrahigh-temperature resistance

Continuous ceramic fibers with ultrahigh-temperature stability are in high demand for applications in advanced space propulsion and thermal protection systems. In this study, SiC nanograins stabilized Si-C-B-N ceramic fibers were prepared using chemically modified polyborosilazane via a polymer-derived method. The fabricated Si-C-B-N fibers exhibited a rather high tensile strength of approximately 1.8 GPa and a high strength retention of approximately 90% after annealing at 2100 degrees C for 0.5 h under a nitrogen atmosphere. The ultrahigh-temperature stability can be contributed to the presence of thermodynamically stable SiC nanograins and the encapsulation of SiC nanograins by the BN(C) phase and amorphous Si-C-B-N matrix. Our work offers a convenient strategy for preparing Si-based ceramic fibers with ultrahigh-temperature stability at beyond 2000 degrees C.

Automated summary

This study prepared SiC nanograins stabilized Si-C-B-N ceramic fibers using chemically modified polyborosilazane via a polymer-derived method. The fibers exhibited high tensile strength and strength retention after annealing, attributed to the presence of thermodynamically stable SiC nanograins and the encapsulation effect.