Lubrication Lubrication is the control of friction and wear by the introduction of a friction-reducing film between moving surfaces in contact. The lubricant used can be a fluid, solid, or plastic substance.

Many different substances can be used to lubricate a surface. Oil and grease are the most common. Grease is composed of oil and a thickening agent to obtain its consistency, while the oil is what actually lubricates. Oils can be synthetic, vegetable or mineral-based as well as a combination of these.

The application determines which oil, commonly referred to as the base oil, should be used. In extreme conditions, synthetic oils can be beneficial. Where the environment is of concern, vegetable base oils may be utilized.

Function of lubricant The functions of a lubricant are to:

Reduce friction Prevent wear Protect the equipment from corrosion Control temperature (dissipate heat) Control contamination (carry contaminants to a filter or sump) Transmit power (hydraulics) Provide a fluid seal Sometimes the functions of reducing friction and preventing wear are used interchangeably. However, friction is the resistance to motion, and wear is the loss of material as a result of friction, contact fatigue and corrosion. There is a significant difference. In fact, not all that causes friction (e.g., fluid friction) causes wear, and not all that causes wear (e.g., cavitational erosion) causes friction.

Reducing friction is a key objective of lubrication, but there are many other benefits of this process. Lubricating films can help prevent corrosion by protecting the surface from water and other corrosive substances. In addition, they play an important role in controlling contamination within systems.

The lubricant works as a conduit in which it transports contaminants to filters to be removed. These fluids also aid in temperature control by absorbing heat from surfaces and transferring it to a point of lower temperature where it can be dissipated.