乙醇为前驱体冷壁CVD法炭单丝表面制备热解炭涂层及其微观结构

The preparation and microstructure of pyrolytic coating on carbon monofilament by cold wall CVD using ethanol as precursor

采用炭基体单丝直接通电加热的冷壁化学气相沉积工艺,以无水乙醇为前驱体,在大直径沥青基炭单丝表面沉积了热解炭涂层。通过扫描电子显微镜和拉曼光谱技术表征了热解炭的形貌和微观结构,并计算了涂层轴向表面的晶粒尺寸。结果表明,随着沉积温度的升高,由于乙醇热解活化自由能变小,热解炭微观结构变得有序,晶粒尺寸变大;随着乙醇流量的增加,基体表面的反应物种浓度提高,使晶粒尺寸有变小趋势。一定工艺条件下制备的热解炭涂层具有完好的晶体结构,其拉曼谱峰中类似于完好结构单层石墨烯的拉曼谱峰峰型,I_(2700)/I_G值约为2.23,表明该工艺条件下热解炭晶粒尺寸分布范围小,缺陷较少。

Pyrolytic carbon coating was fabricated using ethanol as precursor on pitch-based carbon monofilament by cold wall chemical vapor deposition. Scanning electron microscopy （SEM） and Raman spectroscopic analysis were used for the characterization of microstructure of samples. The results indicate that the deposition temperature is favor for the orientation of microstructure and the growth of crystal simultaneously, the increase of flow rate of C2H5OH makes the crystal size smaller which is due to the increase of concentration of reactive species nearby the substrate surface. On proper fabrication conditions, the pyrolytic carbon coating has a Raman spectrum similar to that of the graphene. The I2700/IG is about 2.23, implying that the coating has narrow crystal size distribution and little defect.