A lubricating grease consists of a base oil, performance additives and a thickener which forms a matrix that retains the oil in a semisolid state. Most grease thickeners are soaps, i.e. lithium, calcium, or aluminium soap. Complex soap greases have superior temperature resistance and are commonly usable up to 180C, at which the mineral oil vaporizes. A smaller number of greases, restricted to very special applications, are manufactured with non-soap thickeners such as organoclays, polyurea or silica compounds.

Grease is the most widely used lubricant for roller bearings and low viscosity applicantons, mainly because grease type lubricants are relatively easy to handle and require only the simplest sealing devices. The selection of the type op lubricant, oil versus grease, and the lubricating system depends mainly on ...