Study on Structure and High Temperature Stability of SiBN Ceramic Fibers

The molecular precursors were synthesized with boron trichloride (BCl₃), trichlorosilane (SiHCl₃) and hexamethldisilazane (Me₆Si₂NH) as raw materials by one-step copoly condensation, and then polymerized to polyborosilazane (PBSZ), and SiBN ceramic fibers were finally obtained after spinning, curing and pyrolysis of PBSZ.The structure and high temperature stability of SiBN ceramic fibers were investigated by a series of characterization methods such as FT-IR, NMR, TG, XRD, TEM, etc.The results showed that there were mainly SiN₄ and B-N hexatomic rings after SiBN ceramic fibers pyrolysized, indicating the existance of inorganic transfermation.The SiBN ceramic fiber lost 1%of weight at 850℃ and remained amorphous structure at 1 400℃, presenting the excellent high temperature stability.