Reductive heat treatment of austenitic stainless steel substrate for growth of hybrid carbon nanostructures

Single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and carbon nanofibers (CNFs) in hybrid structures were synthesized on austenitic stainless steel substrates (Type:304). The formation of nanoparticles on substrates occurred under hydrogen gas (H₂) with temperature of 720 °C. The effects of reductive heat treatment on the growth of carbon nanostructures at 15, 45, 60, 75 and 80 minutes were examined with scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractrometer (XRD) and thermogravimetric analysis (TGA). The samples were synthesized using thermal chemical vapor deposition (Thermal CVD) under atmospheric pressure of acetylene gas (C₂H₂). The combination of carbon nanotubes and carbon nanofibers in hybrid structure was synthesized on a substrate using a long time to adjust the surface by heating treatment. The hybrid structure of carbon could not be observed when used in surface treatment time was 80 minutes. Shorter (<;45 min) or longer (>75 min) substrate heat treatments did not produce hybrid carbon nanostructures at this temperature.