锆/锂取代反应合成聚锆硼硅氮烷和热解制备陶瓷

Synthesis of Polyzirconborosilazane via Zirconium/Lithium Substitution and Pyrolysis to Ceramics

采用前驱体分子结构设计的方法,通过氨解、硼氢化反应制备聚硼硅氮烷(PBSZ)。以氯化锆为锆源,通过锆/锂取代反应将锆原子引入PBSZ中,合成聚锆硼硅氮烷(PZrBSZ),在氩气保护下1100℃热解制备含锆硅硼碳氮(SiZrBCN)陶瓷。研究了锆/锂取代反应的特征、PZrBSZ的形成过程,表征了PZrBSZ的化学结构。采用红外光谱分析PBSZ和PZrBSZ,对比发现PZrBSZ在584和917 cm-1处出现特征峰,推测分别对应为Zr—N和Si—N—Zr的特征峰,表明通过锆/锂取代反应已成功将Zr原子引入到前驱体分子中。通过扫描电镜观察PZrBSZ在氩气中热解制得的SiZrBCN,发现其断面虽有气孔但局部致密,这表明PZrBSZ热解可制备SiZrBCN陶瓷。

The precursor-polyborosilazane(PBSZ)is synthezed via ammonolysis and hydroboration reactions with the precursor molecular structure design.Polyzirconborosilazane(PZrBSZ)is obtained via incorporating Zr atoms into PBSZ network by zirconium/lithium substitution reaction.The PZrBSZ is pyrolysed to SiZrBCN ceramics at 1100℃in a flowing argon atmosphere.The characteristics of zirconium/lithium substitution reaction and the preparation process of PZrBSZ are studied.The chemical structures of the PZrBSZ are analyzed by FTIR.In the FTIR spectra,the characteristic peaks at 584 and 917 cm-1 can be assigned to Zr—N and Si—N—Zr stretching respectively,indicating that zirconium atoms have been successfully introduced into the precursor-polyborosilazane by zirconium/lithium substitution reaction.SEM observes that the ceramics have pores but are compact partly in the cross-section after the pyrolysis of PZrBSZ,which indicated that SiZrBCN ceramics could be prepared by pyrolysis of PZrBSZ.