Jump to navigation Jump to search Grease is a solid or semisolid lubricant formed as a dispersion grease bannock recipe thickening agents in a liquid lubricant. A common feature of greases is that they possess a high initial viscosity, which upon the application of shear, drops 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 shear thinning.

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 ingress of water and incompressible materials. Grease-lubricated bearings have greater frictional characteristics because of their high viscosity. An inverse micelle formed when a soap is dispersed in an oil. This structure is broken reversibly upon shearing the grease.

Soaps are the most common emulsifying agent used, and the selection of the type of soap is determined by the application. Powdered solids may also be used as thickeners, especially as clays. Fatty oil-based greases have also been prepared with other thickeners, such as tar, graphite, or mica, which also increase the durability of the grease. The amount of grease in a sample can be determined in a laboratory by extraction with a solvent followed by e.