What Is Lubricant?

Lubricant is a material or substance applied to reduce the friction between the moving surfaces. There are number of industrial applications of the lubricants. One of the most common applications of lubricants is in the form of motor oil, which is used to protect the combustion chambers of the vehicles, as well as other powered equipments.

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Characteristics Of A Good Lubricant:

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A lubricant is considered as effective, and efficient, if it possess the following properties:

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• Low freezing point


• High boiling point


• Thermal stability


• Prevention from corrosion


• Higher viscosity index


• High resistance to oxidation

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Types Of Lubricants

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• Petroleum Lubricants:

Petroleum products are the most common lubricants among others.These are the first preference for typical processes, because of being in expensive in comparison with other lubricants. These petroleum lubricants are used for a wide range of application sectors, like engines, gears,transmissions etc. these petroleum products are known by their viscosity indexes or ASTM codes. However some of the common petroleum lubricants are gear oils, motor oils, automatic transmission fluids, valve oils etc.

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• Synthetic oils

These are also the petroleum based lubricants, but are more modified, and that is why quite expensive then the simple petroleum products.The typical uses of different types of synthetic oils are in auto engines, jet engines, air craft hydraulics, rubber seals, fire resistance fluids, and number of others.

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• Greases

Grease is basically lubricating oil which is thickened with a gelling agent. Greases are the first considerations for the lubrication of bearings in electric motors, machine tools, house hold appliances, as well as the slow speed moving equipments. Common gelling agents used to make greases are the fatty acids of soap (like oleic, palmitic and other carboxylic acids),clay particles of bentonite and hectorite, carbon black, silica and several others.

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• Solid film lubricants

These solid film lubricants provide thin films of solids,between the moving surfaces, to reduce friction and wear. Solid film lubricants are classified as inorganic (molybdenum disulfide, graphite etc) and organics(ethylene-propylene copolymer etc).

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Lubricants Additives

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The common additives used in the lubricants are

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• Foam inhibitors


• Oxygen inhibitors


• Viscosity index improver


• Rust inhibitors


• Anti-wears


• Pour point depressants


• Extreme pressure agents


• Friction modifiers


• Detergents and dispersant

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What Is Lubricant?

Lubricant is a material or substance applied to reduce the friction between the moving surfaces. There are number of industrial applications of the lubricants. One of the most common applications of lubricants is in the form of motor oil, which is used to protect the combustion chambers of the vehicles, as well as other powered equipments.

Characteristics Of A Good Lubricant:

A lubricant is considered as effective, and efficient, if it possess the following properties:

• Low freezing point
• High boiling point
• Thermal stability
• Prevention from corrosion
• Higher viscosity index
• High resistance to oxidation

Types Of Lubricants

• Petroleum Lubricants:

Petroleum products are the most common lubricants among others. These are the first preference for typical processes, because of being inexpensive in comparison with other lubricants. These petroleum lubricants are used for a wide range of application sectors, like engines, gears, transmissions etc. these petroleum products are known by their viscosity indexes or ASTM codes. However some of the common petroleum lubricants are gear oils, motor oils, automatic transmission fluids, valve oils etc.

• Synthetic oils

These are also the petroleum based lubricants, but are more modified, and that is why quite expensive then the simple petroleum products. The typical uses of different types of synthetic oils are in auto engines, jet engines, air craft hydraulics, rubber seals, fire resistance fluids, and number of others.

• Greases

Grease is basically lubricating oil which is thickened with a gelling agent. Greases are the first considerations for the lubrication of bearings in electric motors, machine tools, house hold appliances, as well as the slow speed moving equipments. Common gelling agents used to make greases are the fatty acids of soap (like oleic, palmitic and other carboxylic acids), clay particles of bentonite and hectorite, carbon black, silica and several others.

• Solid film lubricants

These solid film lubricants provide thin films of solids, between the moving surfaces, to reduce friction and wear. Solid film lubricants are classified as inorganic (molybdenum disulfide, graphite etc) and organics (ethylene-propylene copolymer etc).

Lubricants Additives

The common additives used in the lubricants are “

• Foam inhibitors
• Oxygen inhibitors
• Viscosity index improver
• Rust inhibitors
• Anti-wears
• Pour point depressants
• Extreme pressure agents
• Friction modifiers
• Detergents and dispersant

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What Is Lubrication?

Lubrication is the process or method used for the reduction of friction and wear of the moving surfaces by applying an additional substance between the surfaces. This substance is called as Lubricant. While the study of this lubrication science,friction, and wear is called as Tribology.

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Lubrication is necessary for the correct operations of the mechanical operations works on the contacting- rubbing phenomena, like pumps, pistons, turbines, bearings etc.so that the pressure generated by the contact between the surfaces can be minimized,and so is the risk of wear- tear as well as friction losses.

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Regimes Of Lubrication

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There are several distinct regimes which are commonly used to describe the fundamental principles of lubrication. When the load increases on the surfaces in contact, usually following distinct regimes are observed, with respect to the lubrication modes. These regimes are called as regimes of lubrication.

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• Fluid film lubrication

In fluid film lubrication regime, the moving surfaces have a liquid or gaseous lubricant film between them, so that the contact between the surfaces can be avoided. So both the frictional power loss, as well as the pressure is the functions of lubricant viscosity, as well as the shear rate and geometry of the contacting surfaces. This regime is common in electric motors,and generators.

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• Boundary lubrication

Boundary lubrication regime is used for the worse conditions,where the fluid film lubrication is not enough to cover the applied load severity. I.e. when the bodies come in contact, heat generated by the by the load causes stick-slip conditions, which can lead to breakage. At high pressure and temperature conditions, the reactive particles of the lubricant reacts with the contacting surfaces forming a layer on the moving surfaces, this layer is highly resistive and can support the load, so can avoid the breakage. This lubrication layer is often considered as the boundary film lubrication. The most common example of boundary film lubrication is Hypoid gears in automobiles.

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• Elastohydrodynamic lubrication (EHL)

This regime of lubrication is the lubrication between the non-conformal surfaces contact, i.e. the contact between those surfaces, which do not fit each other, such as bearings (ball and roller), cams, gear teeth, or other friction drivers. By understanding EHL, it can be predicted that how thick lubricant films should be formed on the basis of the contacting pressure magnitudes and the surface stresses.

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It is not enough to know about the lubrication regimes, as there are several different lubricants, which are used in any of the lubrication regime. So a detailed study of tribology is needed to understand any friction-lubrication case.

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What Is Tribology?

what is tribology

The term“Tribology” is derived from a Greek work “Tribos” which originally means“rubbing”. So the simplest way to explain What Is Tribology is that “Tibology”is the analysis of the rubbing surfaces, i.e. the friction, wear and lubrication analysis. It is a complete science it self, which deals with the detailed study and analysis of four major factors involved for the prevention from wear and tear of the sliding surfaces:

• Corrosion: destruction or degradation of material by electrochemical or chemical reactions between the surface and environment.


• Abrasion : It is a mechanical process, in which the sliding surfaces start scratching or scuffing away.


• Adhesion: It is the attraction between dissimilar particles or the surfaces


• Erosion: Layer by layer degradation or destruction of material surface.

It not only helps in minimizing the wear and tear of the surfaces, but also helps in extending the working life of the equipments. Although tribology is more about mechanical engineering, then chemical engineering; but the processes under tribology tree are more concerned with the chemical engineering. Out of them, Lubrication is the most important.

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Lubrication is probably the vital science, used in the field of Tribology. Lubrication works by making the surfaces in contact more slippery and greasy to eliminate several factors like overheating, friction, or tearing. There are several different types of Lubricants, which are used for different surfaces; most important of them are Petroleum lubricants, Synthetic Oils, Greases, Solid film lubricants and Metal films.

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The application sectors of the tribology are unlimited, from a little lip gloss to the very large machinery or equipment, every single substance, which has to slide on any other substance, is designed by keeping the rules of tribology in mind. With the help of tribology, the friction losses, and other heat losses are minimized, and so is the operational cost of the process.

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