以三氯化硼、甲基氢二氯硅烷、六甲基二硅氮烷为起始原料,通过共缩合路径合成了SiBNC陶瓷先驱体－聚硼硅氮烷(PBSZ),将PBSZ在氨气气氛中高温热解可得SiBNC陶瓷. 对先驱体及其陶瓷产物的组成、结构和高温结晶性能进行了研究. 结果表明, 先驱体的骨架结构为-Si-N-B-,其中, B、N以硼氮六环形式存在. 1000℃的陶瓷产率为61%, 陶瓷中碳含量低于0.5%,具有较好的热稳定性能, 能够在1700℃以上保持非晶, 在1850℃部分结晶,主要由Si3N4、BN和少量SiC组成, 1500℃-1850℃间质量损失约为10%.
Polyborosilazane (PBSZ), a precursor to SiBNC ceramic, was synthesized via cocondensadition approach using methyldichlorosilane (MeHSiCl2), boron trichloride (BCl3) and hexamethydisilazane (HMDZ) as the starting materials. SiBNC ceramics were obtained when pyrolysising the as-synthesized PBSZ in NH3/N2 atmosphere. The chemical composition, structure and high temperature properties of the obtained polymer and ceramics were investigated using EA, FTIR, NMR, XPS and XRD. The results indicate that the backbone of PBSZ is －Si－N－B－ linkage in the form of borazine and C is in the form of Si－CH3. The ceramic yield of the PBSZ at 1000 ℃ in NH3/N2 atmosphere is 61％. The products have low carbon content (<0.5％)and show excellent high temperature stability. They are fully amorphous after heated to 1700 ℃ and result in partially crystallized Si3N4、BN、SiC phases when heated to 1850 ℃.The weight loss of SiBNC ceramics at 1500 ℃～1850 ℃ is about 10％.
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