Qin Jianjie, Wang Chengguo, Yao Zhiqiang, Ma Ziming, Cui Xuanhao, Gao Quan, Wang Yanxiang, Wang Qifen, Wei Huazhen
Key Laboratory of Liquid-Solid Structural Evolution and Processing of Materials of Ministry of Education, State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, 250061, People's Republic of China.
Carbon fiber Engineering Research Center, School of Material Science and Engineering, Shandong University, Jinan 250061, People's Republic of China.
Nanotechnology. 2021 Apr 20;32(28). doi: 10.1088/1361-6528/abf50f.
Carbon nanotubes (CNTs) were continuously grown on the surface of the moving carbon fiber by chemical vapor deposition method using a custom-designed production line to prepare composite reinforcements on a large-scale. The systematic study of different parameters affecting the CNT growth revealed simple growth kinetics, which helps to control the surface morphology and structural quality of CNTs. Since hydrogen maintains the activity of the catalyst, it promotes the growth of CNTs in a continuous process. The increase of acetylene partial pressure promotes the accumulation of amorphous or graphite carbon on the catalyst surface, resulting in the decrease of CNT growth rate when acetylene concentration reaches 40%. The growth temperature significantly affects the CNT diameter and structural quality. As the temperature increases, the crystallinity of the tube wall increases obviously, and the CNT diameter increases due to the aggregate growth of the catalyst particles. According to the Arrhenius formula, the apparent activation energy is observed to be 0.67 eV, which proves that both bulk diffusion and surface diffusion exist when activated carbon passes through the catalyst to form CNTs.
采用定制设计的生产线，通过化学气相沉积法在移动的碳纤维表面连续生长碳纳米管，以大规模制备复合增强材料。对影响碳纳米管生长的不同参数进行的系统研究揭示了简单的生长动力学，这有助于控制碳纳米管的表面形态和结构质量。由于氢气维持催化剂的活性，它在连续过程中促进碳纳米管的生长。乙炔分压的增加促进了非晶态或石墨碳在催化剂表面的积累，当乙炔浓度达到40%时，导致碳纳米管生长速率降低。生长温度显著影响碳纳米管的直径和结构质量。随着温度升高，管壁的结晶度明显增加，并且由于催化剂颗粒的聚集生长，碳纳米管直径增大。根据阿伦尼乌斯公式，观察到表观活化能为0.67电子伏特，这证明当活性炭通过催化剂形成碳纳米管时，体相扩散和表面扩散都存在。
