Catalytic growth of carbon nanotubes on stainless steel: Characterization and frictional properties

Carbon nanotubes (CNTs) have been grown both on a sample of stainless steel (317-2R) and on the same steel coated with cobalt colloid nanoparticles. Both materials are suitable supports for the growth of vertically aligned carbon nanotubes, although a more sparse growth of significantly thicker carbon nanotubes is observed in the case of the bare steel. We find that carbon nanotubes grown directly on the stainless steel support show very poor tribological behaviour whereas the support using nanoparticles for carbon nanotube growth displayed interesting tribological properties with friction coefficients of approximately 0.1-0.2. The modified CNT material (studied by Raman spectroscopy) adheres to both mating surfaces avoiding direct contact between asperities and plough so the friction and wear processes decrease greatly.