Tribology: The study of bodies in sliding contact.
Annapolis, MD 21402
Questions or Comments: email Assoc. Prof. J.A. Harrison
Introduction
| The ubiquitous nature of friction has made understanding and controlling it paramount to many areas of technology. Indeed, for some applications, such as the lubrication of automobile engines, low friction (and wear) are desired. Other applications, such as the brakes on automobiles, require high friction. Clearly, a detailed understanding of the mechanisms that govern friction (and related phenomena such as wear) is required to influence the friction experienced between two bodies in sliding contact. With this in mind, the friction between macroscopic bodies in sliding contact has been studied since the time of Leonardo da Vinci (1452-1519). These studies have given rise to the so-called classic laws of friction. These are the laws of friction one would find in typical Physics and Engineering textbooks. These empirical laws describe friction in general terms and have given rise to some general ideas that attempt to explain friction. It should be noted, however, these classic laws do not explain the underlying atomic-scale mechanisms that give rise to friction. That is, what happens to the atoms at a sliding interface and how do atomic events affect friction? Recent advances in scientific instrumentation allow for the examination of friction between very small (on the order of microns) contacts. These atomic-scale friction experiments have revealed some of the atomic-scale mechanisms of friction. Data from these experiments are at odds with some of the classic laws of friction. |
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