lubricating oil additives are chemical compounds that are mixed with lubricant base oils to improve their performance. They are formulated into packages for specific lubricant bases and end-use applications. The market for lubricant additives is driven by global demand for automotive lubricants (heavy-duty, passenger car motor oils and metalworking fluids), industrial lubricants (metalworking and hydraulic fluids) and a range of consumer applications. The addition of lubricant additives increases the life and production of final lubricants and reduces maintenance costs.

The major functional lubricant additives are dispersants, detergents, oxidation inhibitors, antiwear agents and extreme-pressure additives. These are complemented by abrasive and demulsifying agents, viscosity index enhancers and pour point modifiers.

Defoamants prevent foaming in lubricants which disrupts the flow of oil and cooling of parts, leading to a reduction in load carrying capacity and a decrease in lubricant efficiency. Pour point depressants are used to lower the freezing point of mineral oil lubricants; they act by adding large, negatively charged hydrophilic molecules to the surface of the molecule which reduces the intermolecular interactions and allows the molecule to form closer contacts with metal surfaces.

Grease additives such as calcium sulfonate greases, polyurea greases and aluminum complex greases are characterized by low pour points, good rheological properties, high temperature service capability and water tolerance. Other important grease additives include lubricity modifiers, thickeners and tackifiers. Odorants and dyes are added to lubricants and greases to ensure that the products have an acceptable scent and appearance. In the past some mass-marketed lubricant additives such as those containing PTFE/Teflon caused a backlash among consumers and were condemned by U.S. federal regulators.

FEP (fluorinated ethylene propylene) is an excellent alternative to PTFE and is melt-processable making it easier to extrude long continuous lengths. Its low gas permeability and non-stick properties, high dielectric strength, excellent UV transmission rating and inert characteristics make it an ideal choice for a wide variety of applications. It is a very tough polymer that can be heat-formed, tipped, tapered, flared and flanged. It is available in a range of sizes from rods up to 6" diameter to sheets as thick as 2".

Unlike many other plastic materials, FEP is not chemically reactive and is resistant to almost all chemicals except for molten alkali metals, elemental fluorine and fluorine precursors at elevated temperatures. Its inert characteristics also make it well suited for laboratory applications where leakproof Nalgene bottles and centrifuge tubes are preferred over glass. It can also be used for coating surgical instruments and jacketing guidewires. FEP shrinks at 212degF (100degC), much lower than PTFE's minimum of 617degF (325degC).

FEP is also commonly used for UV cured resin 3D printing because it is optically transparent and allows over 97% of UV light to pass through it. It is also a very useful material for making sample holders in microscopy because of its transparency and low coefficient of friction. It is sterilizable with all known chemical and thermal methods, including gamma radiation. Its only drawback is that it is quite expensive to produce because of the need for special molding and processing equipment and the cost of the raw materials.

When used in conjunction with other material such as metal, graphite forms a solid or dry lubricant that reduces friction between surfaces. Graphite lubricant is especially effective in high temperatures and environments where liquid lubricants lose their viscosity, such as when operating in space.

What makes graphite so slippery? It’s a combination of its structure and the weak forces that hold its layers together. At an atomic level, graphite consists of sheets of carbon atoms, with very weak van der Waals bonds between each layer. This allows the sheets to slide on each other with minimal resistance. Graphite’s natural slippage provides lubrication even when applied in very small amounts.

The best way to apply graphite lubricant is to combine it with a fast-evaporating solvent and spray the mixture onto the surface that needs lubricating. This form of application is most commonly seen in the pinewood derby kits and other similar projects, where powder graphite is sprayed onto wheels to help them spin faster.

This process produces a smooth, long-lasting lubricant. Unlike oil, grease and penetrants, it doesn’t leave sticky residues that attract dirt and debris and may contaminate other surfaces.

SLIP Plate, a popular graphite lubricant manufactured by Superior Graphite, is a top-rated dry lubricant that’s safe to use and formulated using the highest quality graphite possible. The company sources its graphite from several mines around the world, which is then processed here in the United States. SLIP Plate’s formulas are made without fillers and other additives, which guarantees that the lubricant contains pure graphite and nothing else.

In the field of dry lubricants, molybdenum disulfide is currently a popular choice, especially in aerospace applications. In contrast to other lubricants, MoS2 can withstand high loads for an extended period of time. However, the lifetime of a mos2 coating is limited by its adhesion properties with the base material.

A key aspect of adhesion between MoS2 and a substrate is the occurrence of possible chemical reactions. It is therefore crucial to ensure that the base material provides a strong binding with the molybdenum disulfide layer in order to avoid a premature coating failure.

In this study, two magnetron sputter-deposited mos2 coatings (a nanocrystalline one and a porous one) were compared to a CVD grown 2H-MoS2 single crystal using high-resolution transmission electron microscopy in selected area electron diffraction mode. The atomic structure of the MoS2 lamellae in both the as-deposited and worn coatings was investigated with a double aberration corrected Titan Themis 300 transmission electron microscope and high-angle annular dark-field scanning TEM techniques.

The morphology of the sputter-deposited MoS2 porous coating was characterised by its open porosity, which consists of a hierarchical, dendritic surface structure with interdendritic voids. In comparison, the morphology of the nanocrystalline coating is characterised by a more compact basal texture.

The tribological behaviour of the porous and polycrystalline coatings was analyzed in ball-on-disk test experiments at a load of 1.17 GPa. Both the coatings exhibited very low friction values in vacuum and ambient air. However, the sputter-deposited porous coating showed significantly higher wear rates than the polycrystalline coating. The wear behaviour of the sputter-deposited porous MoS2 was attributed to the occurrence of a non-crystalline, oxidized layer that inhibited the formation of a continuous tribo-film.

The hardest material known to man is cubic nitride boron, or CBN. It is used in various manufacturing processes for its hardness and strength. In fact, it is so hard that it can cut diamonds.

cubic nitride boron was first synthesized as a crystalline compound in 1957 by Robert H. Wentorf at GE. It is a synthetic refractory that is used for grinding and polishing materials. CBN is a very stable material that has high thermal and chemical resistance. It is especially well suited for machining ferrous metals such as iron and its alloys, because it has superior hardness to conventional diamond abrasives. It also has higher thermal stability and is less reactive than diamonds with standard transition metals.

Boron nitride exists in three polymorphic forms: hexagonal boron nitride (h-BN), sphalerite boron nitride (b-BN) and wurtzite boron nitride (g-BN). Hexagonal and sphalerite boron diffraction patterns are similar to graphite and lonsdaleite, respectively. Hexagonal boron nitride and wurtzite boron are very similar to diamond. They have a complex crystal structure and interpenetrating face-centred cubic lattices.

In contrast, b-BN has a simpler tetragonal structure and g-BN is triangular with one atom missing. It is a gray to black solid with a metallic luster. It is very resistant to shock and impact damage, being harder than steel and more resilient than diamond. It has high thermal and chemical stability, making it a popular refractory for crucibles and other furnace parts. It also exhibits good mechanical properties for cutting and grinding applications.

A vehicle's differential transfers power from the engine to the drive wheels, using the difference in rotational speed of the inside and outside axles. An "open" differential allows the inside and outside wheels to turn at different speeds, but a limited slip or positraction differential is designed to deliver a more even amount of torque to each wheel, resulting in more controllable acceleration, less wheel-spin in turns and improved overall handling.

However, over time as the clutches in a limited-slip differential wear the differential can start to chatter, creating an annoying shudder that can only be eliminated by the use of a friction modifier. Friction modifiers work by lowering the lubricant's frictional properties, making the lubricant much slicker. This reduces the traction losses created by shear and churning (decreased viscosity).

AMSOIL synthetic gear lubes are limited-slip capable and do not require an additional friction modifier additive, but depending on the differential's friction material and degree of clutch wear chatter may still occur. The addition of AMSOIL Slip Lock eliminates chatter in mechanically sound differentials and is compatible with all petroleum and synthetic gear lubes.

When added to non-limited-slip API GL-5 gear oil a four ounce bottle of the Red Line differential friction modifier will significantly reduce break-in temperatures and frictional damage caused by shear conditions. This will improve the differential's ability to function in its intended manner under heavy loads. The additive can be used to prevent differential chatter in limited-slip or positraction units and also to break-in new differentials.

PTFE is one of the most versatile and popular polymers. It was discovered serendipitously in 1938 by Roy Plunkett, a chemist for the E.I. du Pont de Nemours & Company (now DuPont) when he inadvertently coated the metal equipment used in processing radioactive materials for the Manhattan Project with gaseous tetrafluoroethylene refrigerant. Originally called Teflon, it became widely used in the 1960s as nonstick cookware.

Unlike most other polymers, PTFE is a dense, strong material with a high melting point and good mechanical properties. It is very resistant to chemicals and solvents. PTFE can be made into various grades and sizes for a variety of applications, from micro-machined parts to hoses and tanks. It has excellent dielectric properties with very low group velocity dispersion at radio frequencies. This makes PTFE an excellent choice for use in wiring, notably for aerospace and computer applications.

The chemical inertness of PTFE comes from the fact that its molecules are surrounded by an outer shell of fluorine atoms. This makes the carbon atoms almost completely shielded and gives it one of the strongest chemical bonds in organic chemistry, the C-F bond. This, along with its insolubility, accounts for its nearly total chemical inertness.

Among the most important co-monomers of PTFE are hexafluoropropylene (HFP), perfluoroethylene propylene vinyl ether (PFEP) and perfluoroalkoxy (PFA). These can be incorporated into the basic PTFE chain to make modified polymers that resemble more general melt processable thermoplastics, with phase transitions accompanied by a readily discernible change in the morphology.

Cubic Boron Nitride (CBN) is an extremely hard abrasive that is used to grind materials such as ferrous metals, ceramics and some super alloys. It has a Mohs scale hardness rating of 10, second only to diamond on the scale. It has excellent abrasion resistance and superior chemical stability versus carbon. CBN is able to work at much higher temperatures than pure diamond and can be used for grinding high-speed steels without degradation.

It is very stable under elevated temperatures and can be annealed at 1,600 to 2,400°C (3,700 to 4,800°F) without losing its hardness. Its thermal conductivity is among the highest of all metals and a high-density crystalline structure makes it an effective electrical insulator. It is a very important component of abrasive technology and can be used in a variety of applications.

CBN can be made in a variety of ways, including consolidated with high pressure and temperature techniques and by spark plasma sintering. It can also be formed in a nanostructure using the Hall-Petch effect with a grain size of 14 nm, which increases its mechanical properties. The most commonly utilized form of cbn is a polycrystalline abrasive that can be densified in hot isostatic pressing or spark plasma sintering with silica as the sintering aid.

CBN is available for a wide range of products and can be produced to customer specifications. Several deposition methods have been developed to improve film thickness, crystallinity, residual stress and adhesion. Ion-assisted physical vapor deposition and chemical vapor deposition have been successfully employed to deposit cBN coatings on various substrates.