Tribology is the science and technology of interacting surfaces in relative motion. It includes the study and application of the principles of friction, wear and lubrication. The word “tribology” derives from the Greek τρίβω (“tribo”) meaning “(Ι) rub” (root τριβ-), and λόγος (“logos”) meaning ‘principle or logic’.
The study of tribology is commonly applied in bearing design, where any product of one material slides or rubs over another is affected by complex tribological interactions. However, in recent years the tribology sees its extension into almost all other aspects, whether lubricated in various biological systems, such as microcirculation of red blood cells in capillaries, blinking of eye and contact lens, and respiratory motion between pleural surfaces and articulation in synovial joints like, hip implants and other artificial prosthesis or unlubricated as in high temperature sliding wear in which conventional lubricants cannot be used but in which the formation of compacted oxide layer glazes have been observed to protect against wear. The study even extends to such unlikely areas as hair conditioners and cosmetics such as lipstick, powders and lipgloss.
Historically, Leonardo da Vinci (1452-1519) was probably the first to enunciate two laws of friction. According to da Vinci, the frictional resistance between two different objects of same weight but making contacts over different widths and lengths is same. He also observed that the force needed to overcome frictional resistance is doubled when the weight is doubled. Similar observations were made by Charles-Augustin de Coulomb (1736-1806). The first reliable test on frictional wear was carried out by Charles Hatchett (1760- 1820) using a simple reciprocating machine to evaluate wear on gold coins. He found that compared to self-mated coins, coins with grits between them wore at a faster rate. The deciphering of da Vinci’s work took several centuries, before the development of this branch of science, today called “tribology”.