Atomic scale friction nanotribology

B. Bhushan, J. N. Israelachvili, U. Landman. Nanotribology friction, wear and lubrication at the atomic scale. Nature (London) 374 607-616, 1995. 

The availability of new experimental methods at the end of the 1980 s allowed us to study friction on the atomic scale and created the new field of nanotribology. The observed wearless friction on this scale can be understood using the model of Tomlinson where the plucking action of one atom on to the other leads to energy dissipation via the generation of phonons. 

We are currently in the midst of a new revolution in tribology, driven by (a) the advent of experimental techniques that allow controlled friction measurements at atomic scales and (b) computers that allow the complex dynamics in atomic scale contacts to be analyzed. This new line of study, dubbed nanotribology, is playing a central role in the quest to build robust machines with nanometer-scale moving parts and is poised in turn to beneht from the resulting advances in nanotechnology. 

Nanoindentation and nanotribology have been active research topics since the introduction of experimental tools such as the surface forces apparatus (SFA) and the atomic force microscope (AFM). These tools allow for detailed investigations of frictional properties of confined molecular systems at nanometer length scales(i,2,5,, 5). 

Nanotribology. Nanotribology is the study of how friction, lubrication, and wear occur at the nanometer and sub-nanometer scale, i.e., at the atomic and molecular level. Since the lubricant films currently in disk drives are only about 1 nm in thickness and, within a few years, the carbon overcoats will only be a few nanometers in thickness, improved understanding of how these materials work at the atomic and molecular level to provide tribological protection is critically needed to develop dramatically more effective materials. 

Fundamental rmderstanding of friaion on the atomic and nanometer scales is critical for design of micro- and nanoe-lectromechanical systems. There are two powerful instruments in nanotribology the surface force apparatus and the atomic force microscope. AFM experiments allow high-resolution mapping of friction properties between solids on the nanometer scale and usually indude measurements of friction forces by friction force microscopy (FFM) and adhesion by CFM. In FFM, as a sharp tip scans across a surface in the... 

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