中文摘要：

以聚硼硅氮烷为先驱体,经熔融纺丝、不熔化处理以及在氨气气氛中高温裂解制备了Si-B-N陶瓷纤维.利用元素分析、FTIR、XRD、SEM和波导法等对纤维的组成结构和性能进行了表征.结果表明：Si-B-N纤维的组成为Si1.13BN2.47,室温下纤维的抗拉强度为1.8GPa,弹性模量为196GPa;纤维具有很好的高温稳定性,在惰性气氛中可以保持非晶状态至1700℃,加热至1850℃结晶,形成Si3N4和BN等相.同时,纤维表现出优良的介电性能,室温下,在测试频率为2～18GHz时,其平均介电常数和介电损耗角正切值分别为3.68和0.0042.该纤维有望成为新型耐高温透波复合材料的候选增强材料.

英文摘要：

Si-B-N ceramic fibers with composition Si1.13BN2.47 were prepared by melt-spinning, curing and pyrolysis of a preceramic polyborosilazane. The composition, structure and properties of the fibers were characterized by elemental analysis, FT-IR, X-ray diffraction, SEM and wave-guide methods. The fibers show good room temperature mechanical properties. The average tensile strength （0） and elastic modulus （E） of Si-B-N fibers is 1.8 and 196 GPa, respectively. They also exhibit excellent high temperature resistance and remain amorphous up to 1700 ℃ in inert atmospheres. A mixture of Si3N4 and BN crystalline phases was observed upon heating to 1850 ℃. In addition, the obtained fibers show good dielectric properties according to the measurement by a wave-guide technique. The average dielectric constant （ε） and loss tangent （tan δ） of the as-obtained fibers are about 3.68 and 0.0042 in 2- 18 GHz, respectively. Such performance characteristics make the Si-B-N fiber promising candidate as reinforcement for application to high temperature radar-wave transparent composite materials.