Tribology is the science and technology of interacting surfaces in relative motion. It includes the study and application of the principles of friction, lubrication, and wear. The word "tribology" derives from the Greek τριβο ("tribo") meaning 'to rub', and λόγος ("logos") meaning 'principle or logic'. This article or section is in need of attention from an expert on the subject. ... Friction is the force that opposes the relative motion or tendency toward such motion of two surfaces in contact. ... Lubrication occurs when opposing surfaces are completely separated by a lubricant film. ... In materials science, wear is the erosion of material from a solid surface by the action of another solid. ... This article is about logos (logoi) in ancient Greek philosophy, mathematics, rhetoric, Theophilosophy, and Christianity. ...

Applications

The study of tribology is commonly applied in bearing design but extends into other almost all aspects of modern technology, even to such unlikely areas as hair conditioners and cosmetics such as lipstick, powders and lipgloss. A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. ... Hair conditioners, sometimes called cream rinse, are often used in hair care alongside shampoo, to improve the texture and appearance of human hair. ... Lipstick is a cosmetic product containing pigments, oils, waxes, and emollients that applies color and texture to the lips. ... Powder is a substance that has been crushed into very fine grains. ...

Any product where one material slides or rubs over another is affected by complex tribological interactions, whether lubricated (e.g. hip implants and other artificial prosthesis) or unlubricated (for example, high temperature sliding wear in which conventional lubricants can no longer be used and the formation of compacted oxide layer glazes have been observed to protect against wear). Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ...

Origins

Historically, Leonardo da Vinci (1452-1519) was the first to enunciate two laws of friction. According to da Vinci, the frictional resistance was the same for two different objects of the same weight but making contacts over different widths and lengths. He also observed that the force needed to overcome friction 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". “Da Vinci” redirects here. ... Events October - English troops under John Talbot, 1st Earl of Shrewsbury, land in Guyenne, France, and retake most of the province without a fight. ... Events March 4 - Hernán Cortés lands in Mexico. ... Charles Augustin de Coulomb (born June 14, 1736, Angoulême, France - died August 23, 1806, Paris) was a French physicist. ... Charles Hatchett Charles Hatchett (February 1, 1765 - October 3, 1847) was an English chemist who discovered the element niobium. ... Gold coins are one of the oldest forms of money. ...

The term became widely used following The Jost Report in 1966, in which huge sums of money were reported to have been lost in the UK annually due to the consequences of friction, wear and corrosion. As a result several national centres for tribology were created in the UK. Since then the term has diffused into the international engineering field and many specialists now claim to be tribologists. Year 1966 (MCMLXVI) was a common year starting on Saturday (link will display full calendar) of the 1966 Gregorian calendar. ...

There are now numerous national and international societies, such as the Society for Tribologists and Lubrication Engineers (STLE) in the USA and the Institution of Mechanical Engineers' Tribology Group (IMechE Tribology Group) in the UK. Logo The Institution of Mechanical Engineers (IMechE) is the British engineering society concerned with mechanical engineering. ...

Most technical universities have a group working on tribology, often as part of their mechanical engineering departments. The limitations in tribological interactions are however no longer mainly determined by mechanical designs, but rather by material limitations so the discipline of tribology now counts at least as many materials engineers, physicists and chemists as it does mechanical engineers. Mechanical engineering is an engineering discipline that involves the application of principles of physics for analysis, design, manufacturing, and maintenance of mechanical systems. ...

Fundamentals of Tribology

The tribological interactions of a solid surface's exposed face with interfacing materials and environment may result in loss of material from the surface. The process leading to loss of material is known as "wear". Major types of wear include abrasion, adhesion (friction), erosion, and corrosion. Estimated direct and consequential annual loss to industries in USA due to wear is approximately 1-2% of GDP. ^{[citation needed]}. Wear can be minimized by modifying the surface properties of solids by one or more of "surface engineering" processes or by use of lubricants (for frictional or adhesive wear). Abrasion on the palm of a right hand, shortly after falling Abrasions on elbow and lower arm, still healing. ... Dew drops adhering to a spider web Adhesion is the molecular attraction exerted between bodies in contact. ... Severe soil erosion in a wheat field near Washington State University, USA. For erosion as an operation of Mathematical morphology, see Erosion (morphology) Erosion is displacement of solids (soil, mud, rock and other particles) by the agents of ocean currents, wind, water, or ice by downward or down-slope movement... For the hazard, see corrosive. ...

Engineered surfaces extend the working life of both original and recycled and resurfaced equipments, thus saving large sums of money and leading to conservation of material, energy and the environment.

Methodologies to minimize wear include systematic approaches to diagnose the wear and to prescribe appropriate solution. Important ones include

• Terotechnnology in UK (H. P. Jost, 1972), where a system approach of multidisciplinary engineering and management techniques is used to protect plant, equipment and machinery (assets) from degradation by improving performance in all the functional areas;
• Czichos system approach (H. Czichos,1978) where appropriate material is selected by checking material properties against tribological requirements under operating environment
• Asset Management by Material Prognosis - a concept similar to terotechnology has been introduced recently by the US Military (DARPA) for upkeepment of key equipments in good health and start-ready condition for 24 hours. Good health monitoring system combined with appropriate medication at M&R stages have led to improved performance, reliability and extended life cycle of the assets, like advanced military hardwares and civil aircraft.

In recent years, micro- and nanotribology have been gaining ground. Frictional interactions in microscopically small components are becoming increasingly important for the development of new products in electronics, life sciences, chemistry, sensors and by extension for all modern technology. The Defense Advanced Research Projects Agency (DARPA) is an agency of the United States Department of Defense responsible for the development of new technology for use by the military. ... Nanotribology is a branch of tribology which studies friction phenomenon at a very small scale. ... This article is about the engineering discipline. ... For other uses, see Chemistry (disambiguation). ...

See also

Wikimedia Commons has media related to:

Tribology

• Tribometer
• Wear
• Compacted oxide layer glaze
• Surface engineering

Image File history File links Commons-logo. ... A tribometer is an instrument that measures friction on a surface via a multitude of methods, one which is a ball rolling on the reference surface and giving a relative friction value (called ball on disc). ... In materials science, wear is the erosion of material from a solid surface by the action of another solid. ... Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ... // Solids are composed of a bulk material covered by a surface. ...

Bibliography

• Surface Wear – Analysis, Treatment, and Prevention: R. Chattopadhyay, published by ASM-International, Materials Park, OH, 2001, ISBN 0-87170-702-0.
• Advanced Thermally Assisted Surface Engineering Processes: Ramnarayan Chattopadhyay, Kluwer Academic Publishers, MA (now Springer, NY), 2004.

External links

• What is Tribology? Introduction, Tribology Research Group at Sheffield University (UK)
• Tribology NL a comprehensive overview of tribology from a mechanical engineers point of view