静态化学气相沉积法制备SiC纤维的拉伸强度分布研究

The tensile strength distribution of SiC fibers fabricated by static cold-wall chemical vapor deposition

以沥青基炭单丝为基体,一甲基三氯硅烷为前驱体,使用静态化学气相沉积工艺,在1473K,常压环境下制备了SiC纤维。使用电子万能试验机测试了同一批次纤维的拉伸强度,结果表明其为双峰直方图分布。使用光学显微镜和扫描电子显微镜对纤维的形貌结构进行了表征。沿着反应器方向,不同区域的纤维依次表现为颗粒状、球状、平滑和倒圆锥结构。这些结构的差别导致了纤维力学强度的双峰分布。对沉积机制的分析表明,物料损耗效应和反应器两端的流场稳定性是影响纤维结构的主要因素。

SiC fibers were fabricated by static cold-wall chemical vapor deposition process at 1473K, atmospheric pressure. Methyltriehlorosilane was used as precursor and pitchbased carbon monofilament was used as substrate. The ten- sile strength was tested by electronic universal testing machine and appeared double-peak distribution. The mierostructure was investigated by optical microscopy and scanning electron microscopy. The fibers werechanged from granular,globular, smooth to conical microstructures when progressed along the reactor. The difference between various microstructures resul- ted in the double-peak distribution. Analysis of deposition mechanism indicated that the reactant depletion effect and stabili-