Submitted to: Lipid Technology
Publication Type: Book / Chapter
Publication Acceptance Date: January 20, 2006
Publication Date: March 1, 2007
Citation: Erhan, S.Z., Sharma, B.K. 2007. Lubricants. In: Gunstone, F.D., Harwood, J.L., Dijkstra, A.J., editors. Non Food Uses of Oils and Fats, Lipid Handbook, 3rd Edition, Chapter 9. Boca Raton, FL: CRC Press. p. 591-635.
Lubrication is the use of a material to improve the smoothness of movement of one surface over another, and the material which is used is called a lubricant. Lubricants are usually liquids or semi-liquids, but may be solids or gases or any combination of solids, liquids, and gases. The smoothness of movement is improved by reducing friction. However, this is not always the case, and there may be situations in which it is more important to maintain steady friction than to obtain the lowest possible friction. In addition to simply lubricate the metal parts that comes in contact, lubricants are expected to reduce or control friction of metal parts to save energy, reduce wear or prevent weld of metal surfaces, clean metal surfaces of dirt or sludge to prevent scratching or scoring, clean metal surfaces of water and acids to prevent corrosion and often to prevent overheating. Annual consumption of oil-based lubricants in the USA is close to 10 million tons and valued at more than $8 billion (USD). More than 70% of total lubricant volume is used in motor oils for automotive engines and approximately 10% in hydraulic fluids. Other application areas, mostly industrial lubricants, are less significant.