ABSTRACT
Greases reduce friction and wear and protect the contacting surfaces against moisture and contamination from the surroundings. Greases cannot signi- cantly assist in heat removal from the sliding surfaces nor provide signicant hydrodynamic effects, and they are mainly used for machine components operating in the boundary lubrication regime. Basically, grease is oil, mineral, or synthetic, with a thickener added. Besides the thickener, some chemical agents termed additives are often added to address specic requirements, which include antiscufng (extreme pressure, EP), wear protection (WP), and corrosion inhibiting. Oil is the main component of the grease (85% by weight or more), and its role is to provide lubrication while the thickener retains the oil and prevents its leakage from the lubrication site acting like a sponge. Most thickeners are soaps, such as calcium, sodium, aluminum, or lithium. For special applications, other thickeners may be used.
