Influence of Various Carbon Allotropes on Tribological and Rheological Characteristics of Model Lubricating Systems

Vaseline (VM)–carbon nanostructure (CNS) model systems were studied by rheological and tribological methods. CNSs are represented by materials of various structures: multilayer oxidized graphene (Gr), single-wall (SWNTs) and multi-wall (MWNTs) carbon nanotubes, Taunit-M material, fullerene C60, and shungite nanocarbon. The concentration of CNSs was 0.5 or 1.0 wt %. The influence of the type and concentration of CNSs on rheological and tribological properties of VM–CNS systems has been investigated. The general conclusion for the performed tribological and rheological studies of VM–CNS systems can be considered as the following: an increase in the spatial dimension of the studied carbon allotropes improves the lubrication ability of the base Vaseline. Such influence probably is due to the decrease in the fracture energy of system and the decrease in the thixotropy time.