论文部分内容阅读
在无催化剂条件下,以CH3SiCl3为前驱体,采用化学气相沉积技术(CVD)在C/C复合材料表面制备SiC纳米线。SEM形貌表明:CVD产物有大量数十微米长的纳米线,部分纳米线团聚呈球状,同时也发现类似带刺板栗外壳的短纳米线聚集,且纳米颗粒在其表面沉积等现象。XRD、拉曼光谱和红外光谱分析结果表明,此产物为典型的β-SiC。TEM形貌表明,此类纳米线的直径分布范围为10~100 nm,一些较细的纳米线可通过无定形SiC与较粗的纳米线结合在一起。在一根较粗SiC纳米线的无定形区域长出一根与其直径相近的分支,二者之间的夹角为70°,其与β-SiC晶体中[111]轴堆垛夹角一致。SAED和FFT结果表明,纳米线的生长轴线较多,在纳米线的竹节状区域存在大量堆垛层错和孪晶。边缘弯曲的SiC纳米线晶格面表明,螺旋位错生长为其主要的生长机制。
In the absence of catalyst, SiC nanowires were prepared on the surface of C / C composites by chemical vapor deposition (CVD) using CH3SiCl3 as precursor. The morphology of the SEM shows that there are a large number of nanowires in the CVD product with tens of micrometers in length. Part of the nanowires are agglomerated into a spherical shape. Short nanowires similar to the shell of the prickly chestnut are also found to be aggregated and nanoparticles are deposited on the nanowires. XRD, Raman spectroscopy and infrared spectroscopy analysis showed that the product is a typical β-SiC. The TEM morphology shows that the diameter of such nanowires ranges from 10 nm to 100 nm, and some thinner nanowires can be bound to coarser nanowires via amorphous SiC. An amorphous branch of a thicker SiC nanowire grows a branch with a diameter close to 70 °, which is consistent with the angle of stacking of [111] axis in β-SiC crystal. The results of SAED and FFT show that the growth axis of nanowires is more, and there are a lot of stacking faults and twins in the bamboo-like region of nanowires. Edge-bent SiC nanowire lattice planes indicate that helical dislocation growth is its main growth mechanism.