Grease (lubricant)

Grease is a solid or <a href="/facts/Quasi-solid/ErXfyb5q">semisolid</a> <a href="/facts/Lubricant/9PXISDwU">lubricant</a> formed as a dispersion of thickening agents in a liquid lubricant. Grease generally consists of a <a href="/facts/Soap/S3nJa1oY">soap</a> <a href="/facts/Emulsion/YMSqSCuH">emulsified</a> with <a href="/facts/Mineral_oil/KjXl9BUo">mineral</a> or <a href="/facts/Vegetable_oil/70v8uQMH">vegetable oil</a>.
A common feature of greases is that they possess high initial <a href="/facts/Viscosity/QLVfrdCz">viscosities</a>, which upon the application of shear, drop to give the effect of an oil-lubricated bearing of approximately the same viscosity as the base oil used in the grease. This change in viscosity is called <a href="/facts/Shear_thinning/gX9dSHgP">shear thinning</a>. Grease is sometimes used to describe lubricating materials that are simply soft solids or high viscosity liquids, but these materials do not exhibit the shear-thinning properties characteristic of the classical grease. For example, <a href="/facts/Petroleum_jelly/DWtxuV2g">petroleum jellies</a> such as <a href="/facts/Vaseline/QdLwark9">Vaseline</a> are not generally classified as greases.
Greases are applied to mechanisms that can be lubricated only infrequently and where a lubricating oil would not stay in position. They also act as sealants to prevent the ingress of water and incompressible materials. Grease-lubricated bearings have greater <a href="/facts/Friction/d0108Rpu">frictional</a> characteristics because of their high viscosities.

Grease (lubricant) open-in-new

Grease (lubricant)