What Are Synthetic Lubricants
transmissions and other mechanical systems contain hundreds of moving
parts. Though the metal surfaces of these parts look smooth, they are
actually full of microscopic peaks and valleys. When the peak of one
surface touches its mating surface, it causes damage. Damage may lead to
component failure or wear. Failure prevention and wear reduction are the
primary functions of lubrication.
oils–the oils most people are familiar with are refined from crude oil.
Refining is a process ofphysically separating light oil components from
heavy ones. Crude oil contains millions of different kinds of molecules.
Many are similar in weight but not in structure. The refining process
cannot distinguish such molecules, so a wide assortment of molecules is
the finished lubricant made from crude oil stocks. Some crude oil
molecules are not beneficial to the lubrication process. For example,
parafin causes refined lubricants to thicken and flow poorly in cold
temperatures. Molecules containing sulfur, nitrogen and other elements
invite the formation of sludge and other products of lubricant breakdown,
especially in high-temperature applications. Sludge and breakdown products
significantly increase wear rates. The assorted molecules of refined
lubricants also have different shapes, making lubricant surfaces irregular
at the molecular level. As lubricant layers flow across one another during
the lubrication process, these irregularities create friction, which
consumes power, reduces efficiency and increases heat and wear.
The main advantage of mineral oils is their low cost. The main limitation of mineral oils is that the lubricant-sized molecules have a variety of structures ranging from the best to the worst (in terms of wear control).
A. Jackson, Mechanical Engineering Transactions
lubricants are chemically engineered from pure chemicals rather than
refined from crude oil. That gives them significant advantages over
– The feedstocks from which synthetic lubricants are made do not
contain sulfur, nitrogen or other elements that invite the formation of
sludge and other products of lubricant breakdown. Synthetic lubricants can
be used in higher temperatures than refined lubricants without breaking
down. Their resistance to breakdown also allows them to be used longer
than refined lubricants can be used. Lubricated systems stay cleaner and
last longer with synthetic lubricants.
Synthetic lubricants differ from refined oils in three key ways: synthetics are pure, their molecular structure is uniform, and they may be designed to work in applications in which refined oils cannot.
– The feedstocks from which synthetic lubricants are made feature
uniform and smooth molecular structures, which ensures low friction as
lubricant layers slide across one another. Reduced friction increases
energy through-put for greater fuel efficiency and power and reduces heat
and wear for longer equipment life. Molecular uniformity also helps
synthetics resist thinning in heat and thickening in cold, which helps
them protect better than refined oils over a system’s operating
temperature range and helps ensure secure sealing.
main advantage of mineral oils is their low cost. The main limitation of
mineral oils is that . . . the lubricant-sized molecules have a variety of
structures ranging from the best to the worst (in terms of wear control).
Field experience has shown that synthetics can give economic benfits when
used in place of mineral oils which were working satisfactorily. The
bene.ts fall in five general areas:
Improved energy efficiency •
Wider operating temperature range
Better reliability and safer operation
Mechanical Engineering Transactions
Designable – Many different kinds of feedstocks may be used to create synthetic lubricants, allowing a synthetic to be designed for virtually any application. Some feedstocks are ideal for use in extremely cold environments. Others are perfect for use in extreme heat. Some are extremely safe in applications in which refined lubricants pose a fire or explosion hazard. Refined oils simply do not offer the design flexibility synthetics offer. The design flexibility of synthetics also allows them to be tailored very specifically to the needs of everyday applications, such as automotive engines, commercial equipment or much industrial machinery. That specificity helps ensure long life and peak power, performance and fuel economy from the lubricated system and long lubricant life.