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Greases
Background & Properties
General Information
July 2017
Base Stock
The liquid lubricant portion of a grease can be composed of almost any base oil. A base oil is usually selected for its
low and high temperature performance, oxidation stability and elastomer compatibility. In addition to these
performance characteristics, a base fluid is chosen for the service level and application in which it will work.
The base stock makes up the largest portion of the finished grease and can be a mineral, vegetable, re-refined, partial
synthetic or full synthetic. High viscosity index and oxidation resistance are generally desirable characteristics in a
grease's base fluid.
Additives
Additives enhance the performance of a finished grease. Additives in grease may be either chemically active or
chemically inert. Chemically active additives are ones that chemically affect the grease's performance, such as extreme
pressure agents or rust inhibitors. Chemically inert additives affect a grease's physical properties, like structure or water
tolerance. The most common additives found in grease are anti-oxidants, rust inhibitors, anti-wear agents, extreme
pressure agents and solids.
A premium-performing grease is one that uses top quality additives, a premium base oil and a good thickener. Low
quality grease can seriously impact equipment performance and bottom line results. Research regarding the correct
grease for critical equipment may save money in maintenance and labor in the long run.
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