Parametric investigation of in-situ synthesis of carbon nanotubes on Al2O3 powder by the rotary chemical vapor deposition method

Abstract

A new kind of rotary chemical vapor deposition (R-CVD) system was built to prepare in-situ uniformly dispersed carbon nanotubes (CNTs) on alumina (Al2O3) powder (matrix) by using Ni as catalyst and acetylene (C2H2) as carbon source. The critical CNT growth factors, such as synthesis temperature, growth time, the carbon-source gas-flow rate ratio, and the rotation speed of the furnace tube were investigated for process optimization. In addition, the quality and quantity of the synthesized CNTs on the surface of Al2O3 were investigated by scanning electron microscope (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD), and thermo-gravimetric analysis (TGA). The results showed that the R-CVD allows the use of higher concentrations of a carbon source gas (C2H2:N2 = 1:5) and lower synthesis temperature (500 °C) compared to the traditional CVD process. The synthesized CNTs also exhibit a higher yield rate and more uniform distribution, which has greater application prospects in the field of preparing CNTs reinforced composite materials.