Synthetic Oils, Greases and Lubricants

Synthetic oils, greases and lubricants are based on compounds that consist of boron nitride (BN), chlorofluorocarbons (CFC), esters, diesters, silicone, polyglycol or mixtures of synthetic fluids and water. Synthetic products are generally more expensive than non-synthetic fluids, but provide better fire resistance and cooling performance. The cost and heat transfer performance of semi-synthetic fluids falls between those of synthetic and soluble oil fluids. Some synthetic oils, greases and lubricants are used as circulating coolants, flood or mist coolants, insulating oils, lapping vehicles, lubricants, heat transfer fluids, or thermal oils. Others are used as grinding, metal working, metal forming, metal cutting, hydraulic, transmission, quenchant, or vacuum fluids. Base oils and additives are also available. High water content fluids (HWCF) and high water base fluids (HWBF) are used in applications where leakage is likely to cause ignition. Solid lubricants or dry film lubricants are designed to reduce friction, binding or wear; exclude water; or provide other specialized characteristics.

Synthetic oils, greases and lubricants vary in terms of thermal conductivity, dielectric strength, specific gravity, kinematic viscosity, viscosity index, usage concentration, operating temperature, boiling point, and flash point. Thermal conductivity is a measure of the ability to transfer heat. Dielectric strength is the maximum voltage field that a material can withstand before electrical breakdown occurs. Specific gravity is density normalized to water or another standard. Kinematic viscosity is the time required for a fixed amount of fluid to flow through a capillary tube under the force of gravity. Units of measure include stoke, centistoke (1/100 of stoke) and Saybolt universal seconds (SUS). The viscosity index is based on two temperature extremes. Usage concentration is a volumetric amount. Operating temperature is a full-required range. Boiling point is the temperature at which synthetic oils, greases and lubricants boil. Flash point is the lowest temperature at which substances produce sufficient vapors to form an ignitable mixture in air near the surface. When selecting fire resistant products, fire point and autogenous ignition (AIT) are additional considerations. 

Synthetic oils, greases and lubricants are used in a variety of applications and industries. Some products are designed for aerospace, automotive, marine, or military applications. Others are used with bearings, combustion engines, processing equipment, compressors, piston pumps, gears, and final drives. Passivators or deactivators are applied to internal or machined surfaces. Products with extra pressure (EP) additives form a film to prevent sticking or seizing under heavy loads. Similarly, release agents prevent materials from sticking or adhering to underlying surfaces. Synthetic oils, greases and lubricants can inhibit oxidation, corrosion, or microbial growth; provide sealing or barrier functions; or dampen shock and vibration. Biodegradable products are designed to break down into harmless chemicals when released into the environment. Non-foaming characteristics are achieved through the use of additives that break out entrained air. Synthetic oils, greases, and lubricants that are rated for food, beverage, and pharmaceutical applications are also available. Specialized products include system cleaners, sludge dispersing fluids and detergents.

• Investigation of Lubrication Regimes Using Ultra-Low Contact Pressures
  Measurement of tribology at the micro and nano scales has been limited in recent years by the lack of dedicated instrumentation. The Scanning Force Microscope (SFM) has been the instrument of choice...
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