中文摘要：

1500℃下，采用热蒸发硅碎片的方法，在PAN碳纤维上原位生长碳化硅纳米纤维。讨论了碳化硅纳米纤维的气-固生长机理。X射线衍射图谱表明产物中同时存在碳纤维及βSiC相，通过场发射扫描电镜观察产物，发现碳纤维保持原貌，碳化硅纳米纤维为直线状且表面光滑，直径约为100nm，长度约为50μm。利用透射电镜研究了其形貌和微结构，选区电子衍射图表明该碳化硅纳米纤维为单晶。热蒸发法制备碳化硅纳米纤维有望在碳化硅／碳复合材料等领域得到应用。

英文摘要：

SiC nanofibers were prepared by the thermal evaporation of Si fragments onto the PAN carbon fibers at 1500℃. Vapor-solid growth mechanism of the SiC nanofibers was discussed. The XRD of the as-grown products showed that the products mainly consisted of the beta phase of SiC and the PAN carbon fiber. SEM images showed that the PAN carbon fiber kept its morphology after reacting with Si vapor, and the SiC nanofibers with smooth surlace was straight. The diameter of the SiC nanofibers was about 100 nm and the average length was about 50 μ m. TEM was used to study the morphology and microstructure of SiC nanofibers. The selected area electron diffraction （SAED） pattern demonstrated that the SiC nanofiber had a single crystalline phase. The SiC SiC nanofibers prepared by the thermal evaporation are expected to have great potential for SiC/C composites.