Lubricating Greases can be defined as solid to semi fluid products of the dispersion of a thickening agent in a liquid lubricants. They usually contain additional compounds to impart special properties and usually the thickening agent in a metal soap. It is not easy to classify grease as either liquid or solid. The transmission are fluid. There is no chemical or physical need to describe synthetic greases or fully synthetic greases separately but the term should at least be explained . Many author call a grease synthetic when the base oil is not mineral but a synthetic. Sometime the fully synthetic greases is used when all the additives and other constituents are also synthetic.
The advantages of lubricating greases over oil is that the greases only flows under the influence of a force.
Grease has lower friction coefficients.
Greases cling better to surfaces.
Greases are more water resistant.
The viscosity of grease is less dependent on temperature.
Greases acts as a seals against dirt and other contamination. |