Facile synthesis of homogeneously dispersed carbon nanotubes on TC4 alloy powder by in-situ CVD and its growth behavior

We developed a simple method of in-situ synthesize carbon nanotubes (CNTs) on Ti–6Al–4V (TC4) alloy powder to fabricate CNTs/TC4 compound powders through plasma-enhanced chemical vapor deposition (PECVD). By this approach, CNTs on TC4 alloy powder exhibit better uniform dispersion and morphology compared with the traditional CVD methods. In order to reveal the growth behavior of CNTs during the PECVD process, XRD, SEM, TEM, and Raman spectroscopy were used to analyze the morphology and graphitization of CNTs at different synthesis conditions. The plasma is benefit to the pyrolysis of CH₄, but overmuch plasma bombardment also reduces the yield and quality of CNTs. The number of CNTs can be significantly improved with appropriately increasing the temperature and time, but excessive temperature, time and carbon concentration can increase the number of impurities such as amorphous carbon. Significantly, the growth mechanism of CNTs synthesized in TC4 powders is following tip-growth mode in PECVD process. Additionally, the quantity and quality were satisfactory at 600 °C for 30 min with 50 W plasma power. This study about PECVD process lays a foundation for improving the comprehensive properties of CNTs/TC4 composites in the future.