Chemical, mechanical and tribological characterization of ultra-thin and hard amorphous carbon coatings as thin as 3.5 nm: recent developments

Carbon nanomaterials in tribology

Mechanisms and improvements in the friction and wear behavior using MoS2 nanotubes as potential oil additives

The tribological properties of C(60) on the mesoscopic scale were investigated with a scanning force microscope, which allowed simultaneous measurements of normal and lateral forces under ultrahigh-vacuum conditions. Islands of C(60), deposited on NaCl(001), could be moved by the action of the probing tip in a controlled way. Different modes of motion, such as translation and rotation, were observed. An extremely small dissipation energy of about 0.25 millielectron volt per molecule and a cohesive energy of 1.5 electron volts were determined in these nanometer-scale experiments. The corresponding shear strength of 0.05 to 0.1 megapascal was smaller by one order of magnitude than typical values of boundary lubricants. For C(60) on graphite, disruption of the islands was observed and collective motion of the islands could not be achieved. These results could find use in the field of nanotechnology; for example, C(60) islands could be developed into a sled-type transport system on the nanometer scale.

http://science.sciencemag.org/content/sci/266/5193/1979.full.pdf

Sled-type motion on the nanometer scale : determination of dissipation and cohesive energies of C60

Advances in carbon nanomaterials as lubricants modifiers

The advent of techniques for producing gram quantities of a new form of stable, pure, solid carbon, designated as fullerene, opens a profusion of possibilities to be explored in many disciplines including tribology. Fullerenes take the form of hollow, geodesic domes, which are formed from a network of pentagons and hexagons with covalently bonded carbon atoms. The C60 molecule has the highest possible symmetry (icosaliedral) and assumes the shape of a soccer ball. At room temperature, fullerene molecules pack in a face centered cubic (fee) lattice bonded with weak van der Waals attractions. Fullerenes can be dissolved in solvents such as toluene and benzene and are easily sublimed. The low surface energy, high chemical stability, spherical shape, weak intermolecular bonding, and high load bearing capacity of C60 molecules offer potential for various mechanical and tribological applications. This paper describes the crystal structure and properties of fullerenes and proposes a mechanism for self-lubricatin...

G. W. Van Cleef

Papers

Fullerene (C60) Films for Solid Lubrication

Prediction of the Intensity and Structure of Spectra Associated with the Endohedral motions of Metal-Containing Buckyballs.