Oil Additives and Fluid Additives Information

Oil additives and fluid additives are chemical substances added to oils and industrial fluids to impart or improve certain properties. They are used with lubricants, coolants, thermal oils, greases, and metal working fluids. Oil additives include antioxidants, anti-foam agents, and anti-wear additives; detergents, demulsifiers, friction modifiers, and pour point depressants; viscosity modifiers and deposit control additives; and both anti-corrosion agents and rust and oxidation (R&O) inhibiting additives. Fluid additives for applications such as metalworking include surfactants and emulsifiers, corrosion inhibitors, extreme pressure (EP) additives, biocides, natural lubricants, and products for high-speed machining. Specialty oil additives and fluid additives are also available.

Selecting Oil Additives

Selecting oil additives requires an analysis of product capabilities. Antioxidant additives are designed to resist the oxidation and subsequent decomposition of stock oils. Anti-foam agents prevent the formation of bubbles and foam that may cause corrosion, pitting, and loss of lubrication. Anti-wear additives surround metal parts with a film that prevents rubbing and wear. Detergent additives remove oil impurities that cause sludge to form on engine parts. Demulsifiers are fuel additives that promote the separation of oil and water in lubricants which are exposed to water or steam. Friction modifiers, as their name suggests, are designed to reduce friction between moving parts. Pour point depressants are oil additives that improve the ability to flow at lower temperatures.


Oil additives include viscosity modifiers, deposit control additives, anti-corrosion agents, and rust-inhibiting additives. Viscosity modifiers are used to increase oil viscosity at higher temperatures. Deposit control additives prevent soft sludge and hard deposits, while anti-corrosion agents stop corrosion. Rust-inhibiting are also available. Other types of oil additives include seal conditioners, metal deactivators, and wax crystal modifiers. To prevent the leakage of oil, seal conditioners cause seals and gaskets to swell. Metal deactivators cover metal surfaces with a protective film that prevents oxidation. Wax crystal modifiers are used in petroleum refining and transport, but not for lubricant formation.

Selecting Fluid Additives

Fluid additives vary by application. For example, metalworking fluid additives include surfactants, emulsifiers, corrosion inhibitors, extreme pressure (EP) additives, biocides, and lubricants for high-speed machining. Surfactants are chemical agents that reduce a liquid’s surface tension. Emulsifiers are thickening agents that promote the formation of an emulsion, a colloid in which both phases are liquids. Specialty corrosion inhibitors and EP additives for metalworking applications are also available. Biocides are fluid additives that are used to kill biological organisms. Lubricants for the high-speed machining of metals such as hardened steels are designed to reduce cutting temperatures.