Selected Topics in Contact Mechanics and Nanotribology

Abstract

Driven by recent developments in nanotechnology and materials modeling and simulations, our understanding of contact mechanics, and more specifically of solid friction down to the nanometer scale, is experiencing a period of exceptional growth. Since a dedicated handbook would be not enough to summarize the latest experimental and theoretical achievements, we focus on two selected topics, which will hopefully stimulate the reader to examine the specialized literature in the growing field of nanotribology. These topics are the contact mechanics theory, recently developed by B.N.J. Persson, and the stick–slip motion on the nanoscale. While the first theory, to the best of our knowledge, is the first one embracing the contact between rough surfaces over length scales of several orders of magnitude, and making analytical predictions based on the morphology and material properties of the constituent materials, the second topic concerns the ultimate limits of friction measurements, i. e., the sliding of an atomically sharp tip over a crystal lattice. The two topics are not yet well related, but the situation may change in the near future. For this reason, it is also of interest to mention basic attempts in modeling stick–slip of multi-asperity contacts, as done in an intermediate section of this chapter. Last but not least, the dissipation accompanying the motion of a nanoslider in close proximity to but not touching a solid surface, and oppositely, of a similar object penetrating and scraping the surface, is briefly discussed, as it can be investigated with the most important technique available for this kind of study, i. e., atomic force microscopy.