Structural and Mechanical Behavior of Boron Nitride Fibers Derived from Poly[(Methylamino)Borazine] Precursors: Optimization of the Curing and Pyrolysis Procedures
作者:Pascaline Toutois、Philippe Miele、Sylvain Jacques、David Cornu、Samuel Bernard
DOI:10.1111/j.1551-2916.2005.00685.x
日期:2006.1
A series of boron nitride fibers were prepared by varying the tension applied on a same lot of poly(methylamino)borazine fibers during their pyrolytic conversion at 1800°C. Their microstructure/microtexture was studied by X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy investigations. Such analyses showed that ceramic fibers presented good crystallinity, but crystallites oriented along the fiber axis with fiber stress. It is most interesting that stretching was essentially effective during the pyrolysis to 1000°C, preventing fiber crimping, and decreasing the fiber diameter. Therefore, the fiber strength increased, while the fiber modulus also increased because of an improvement of the basal layer orientation along the fiber axis.
通过在1800°C下对同一批次的聚甲基氨基硼烷纤维施加不同张力进行热解转化,制备了一系列氮化硼纤维。采用X射线衍射、扫描电子显微镜和透射电子显微镜等方法对其微观结构和微观形貌进行了研究。分析结果表明,陶瓷纤维具有良好的结晶性,但晶粒沿纤维轴定向排列,且存在纤维应力。最为有趣的是,拉伸在热解过程中起到了关键作用,防止了纤维卷曲,减小了纤维直径。因此,纤维强度提高,而由于基底层沿纤维轴定向性改善,纤维模量也有所增加。