Experimental and Theoretical Aspects of the Modern Nanotribology

Abstract

A review is given of the present day problems related with experimental and theoretical studies in nanotribology, a new apatterning branch of physics, which pertains to investigations of the atomicscale friction, adhesion, wear and lubrication. When analysing the experimental results a major point of interest is related with ªdryº adhesion friction between the tip of an atomic force microscope and an atomically smooth surface. However, many other physical effects are considered, too, such as chemical ones, triboemission of particles, conduction in metallic nanocontacts, etc. For the first time, some new results in theoretical elaborations of adhesional (static) and dynamical (velocity-proportional) friction are discussed, as well as some results obtained using the computer simulations. A brief discussion of nanostructural friction measured with the quartz crystal microbalance technique and the surface-force apparatus is also given.

Micromechanics of friction: effects of nanometre-scale roughness

“…A typical frictional response of a singleasperity contact is shown as the dot-dashed curve II in figure 1b, where P a is the critical pull-off load. With the wide applications of AFM and SFA, a considerable amount of experimental efforts have been carried out to investigate the single-asperity friction (see Carpick et al 1996a;Lantz et al 1997; and also the reviews by Carpick & Salmeron 1997, Dedkov 2000Gnecco et al 2001). In one of the pioneering works, Carpick et al (1996a) measured the friction of a platinum-coated AFM tip on a mica surface in an ultra-high vacuum (UHV ).…”

Friction traced to the single atom

“…Friction studies have benefited greatly from the invention of the lateral force microscope, introduced in 1987 (2). The resolution power of the lateral force microscope has been improving steadily, opening many applications in high-resolution tribology studies (3)(4)(5)(6) including the study of chemical phase separations (7). However, the observation of single atomic defects-the touchstone of atomic resolution-has not been achieved by lateral force microscopy yet.…”

Nanofriction Behavior of Cluster-Assembled Carbon Films

“…The Atomic Force-Friction Force Microscope (AFM-FFM) has emerged as a powerful tool for the characterization of the tribological properties of materials from the micrometer down to the atomic scale 2,10 . However, the use of a nanometer-sized probe in nano-friction experiments carried out on corrugated samples in humid environments causes the experimental conditions to be usually different from both those encountered in typical ultra high-vacuum experiments, where flat crystalline surfaces are investigated in a humidity and contaminantsfree environment, leading to a single-asperity contact, and those of macroscopic tribology, where the contact regime is always multi-asperity like 11 .…”