Study on Structure and High Temperature Stability of SiBN Ceramic Fibers
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摘要: 以三氯化硼(BCl3)、三氯硅烷(SiHCl3)、六甲基二硅氮烷(Me6Si2NH)为原料,通过共缩聚一步法制备了小分子前驱体,然后经过聚合得到聚硼硅氮烷前驱体(PBSZ),后经熔融纺丝、不熔化处理、高温热解制备出硅硼氮(SiBN)陶瓷纤维。利用FT-IR、NMR、TG、XRD及TEM等分析手段对SiBN陶瓷纤维的组成结构及高温稳定性能进行了表征。研究表明,热解后的SiBN陶瓷纤维主要包括SiN4及BN3结构,其中B—N以六元环形式存在,基本实现了无机化转变,在850℃时失重约为1%,在1 400℃仍然保持非晶结构,具有较好的高温稳定性。Abstract: 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.
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Keywords:
- polyborosilazane /
- SiBN ceramic fibers /
- pyrolysis /
- high temperature stability
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